Free Friday: Today’s top free Amazon sci-fi and fantasy books for April 25, 2025

Reading Time: 10 minutes
Free Friday: Today’s top free Amazon sci-fi and fantasy books for April 25, 2025

Did you know that Amazon has a list of the top-selling and free sci-fi and fantasy books? The list changes constantly — authors and publishers set their books to free temporarily to promote their work, and, of course, books move up and down in the rankings. Read on to find your fun free read for this weekend! And grab the books quickly because they don’t always stay free for long.

This week’s list is completely different from those of the previous weeks. So if you’re a fan of free books, there are going to be new things to read all the time. If you want to get this list in your inbox every Friday afternoon, subscribe to the MetaStellar weekly newsletter.

There are a lot of books to go through, so this week I’m being helped out by a couple of other members of our MetaStellar community. If you’d like to join me in doing these reviews — and taping our regular Free Friday videos — email me at maria@metastellar.com.

5. Mind Machines by Dima Zales

This is the first of three books in the Human++ techno-thriller series by a New York Times and USA Today bestselling author. The other two books are $3.99 each, and are not in Kindle Unlimited. This is not the author’s first time on our Free Friday list. In February of 2022, we reviewed Oasis, the first of three books in The Last Humans young adult dystopian future series.

From Alex Korolov:

People who like futuristic stories — especially those dealing with nanotechnology and creepy medical procedures — will be into this one.

The book starts with a dream. Our main character, Misha, is in an operating room with his Russian mother and grandfather. Misha’s mom is being injected in the neck by a cold-mannered doctor. A giant-sized plunger fills Ava’s neck with a gray goo, which makes her scream as her body dissolves into a puddle of gray, liquid, self-replicating nanocytes. I assume nanocytes are some form of nano robot.

In the next chapter, we learn that Misha owns a company called Techno, which offers nanocyte treatments. Today, his mom is getting a nanocyte injection to help treat some brain damage she suffered in an accident. It turns out her memory was badly damaged, but she can still talk normally. Misha’s mom gets the injection, but it doesn’t melt her into goo. In fact, not much actually happens. I guess it’s not a fast miracle-cure type of treatment.

Then we learn that his mother is the first person to get the experimental treatment, which penetrates the blood-brain barrier to help improve a patient’s brain functions. Misha apparently started his company because of his desire to save his mother’s damaged brain.

This is as far as I got with this story. Besides the dramatic dream that starts this book, it’s a bit of a slow roll. The beginning chapters are all about introducing our main character and his family, and explaining his motivations for starting a nanocyte medical treatment company.

I find the topic of futuristic nano-scale medical technology a really cool topic, and I’m personally excited to see how it will help motor- and brain-impaired humans as the technology develops. Since it’s an interesting topic to me, I plan to keep reading this story to see where it leads. If I had to guess, I bet something crazy will happen with the nanocyte treatments, but I’ll just have to keep reading to find out.

Get the Kindle ebook free from Amazon here.

4. Secrets of the Catalogue by Amelia Spencer

This is the first of four books in The Librarians urban fantasy series. The other books are $2.99 to $4.99 each, but are all in Kindle Unlimited. The fourth book isn’t out yet, but is scheduled to be released at the end of this year and is available for pre-order. This is the author’s first time on our Free Friday list.

From Hannah M:

I love books about magical libraries, so I was excited to read this one.

We immediately jump straight into heartbreak. Our protagonist, Emerson, has just received a break-up text from her boyfriend. He had contracted a mystery illness and became a recluse, distancing himself from Emerson until he finally ended things. The rest of her night is a miserable cycle of drinking and crying.

The next day, she wakes up hung over and late for her shift at the restaurant where she works. Her friend encourages her to go to a nightclub and forget about the breakup. On the train home from work, Emerson encounters a tattooed man and is unable to shake him from her mind all night. From his description, I predict he will be a potential new love interest for Emerson.

At the club, Emerson feels disconcerted and is keen to leave, getting the feeling that someone is watching her. Out on the street, the roads are quiet, with only a single bookshop being open, and she goes home. However, in the morning, she feels an urge to return to the same area. Emerson hops on a train and trusts her intuition to guide her. After hours of walking, she turns into a side street, Bowery Place. Weirdly nobody else seems to be able to see this street.

Upon entering a book shop, Emerson wanders from shelf to shelf and takes out a book titled “The Central Library.” Suddenly, an old man appears behind her and lets her take the book for free. Their meeting is awkward, leaving Emerson feeling unsettled.

I loved this book so far and will continue reading it. I have no idea where the story will go, but I’m so intrigued.

Get the Kindle ebook free from Amazon here.

3. Small Town Aliens by Tasha Black

This is the first box set out of ten in Stargazer Alien Romance Collections by a USA Today bestselling author. The other box sets are $5.99 to $8.99 each, and are also on Kindle Unlimited. This particular box set collects the first three books in the 15-book Stargazer Alien Mail Order Brides sci-fi romance series. This author has been on our Free Friday list before.

From Maria Korolov:

Each time I review one of these books — you know, one of the books with a naked guy’s chest on the cover — I have to give the same disclaimer. I don’t like these books. They’re packed full of all the tropes I hate most — enemies-to-lovers, fated mates, happily ever afters, lust at first sight — and, of course, sex. Lots and lots of very explicit sex.

And yes, I understand how that sounds. It’s like complaining that a chocolate cake is sweet, chocolaty, and covered with frosting. It’s a chocolate cake? What did you expect? Also — people love chocolate cakes. I mean, who wants to eat nothing but brown rice and tofu for the rest of their life? Sometimes you just want to get into a hot tub after a long week of work, light the candles, add the bubble soap, and dig into a big, gooey slice.

What I’m saying is that these books are like cake, okay? And that I’m one of the few people who doesn’t like cake.

Anyway, I’ve bought the box set, opened it, and the first book starts by introducing us to Posey. She’s got a fresh manicure, a pair of tall high heels, a thong, and a silver chain around her neck. That’s it. She’s walking down a runway being ogled by a sea of handsome, tall men in designer suits. One of the men touches her wrist and things start to heat up — I warned you about what kind of book this was — then Posey wakes with a start.

Apparently, she’s been having this dream a lot lately.

Posey is on a train with a couple of friends. They’re all students, on their way to donate their eggs. Posey plans to use the money to help with college tuition. As part of the egg donation process, they all have to spent a month in a small town in Pennsylvania. That seems a little sus, to me.

The town is mostly famous for its observatory and the fact that it sent friendly messages into space. The story is that they got an answer back one day, a thank for the invite to come visit, and that the aliens were on their way. The town rebranded itself as an ET theme park. Nobody showed up, but the town stick with the alien theme.

The three girls get to town and decide to grab dinner at a bar before checking into their hotel. They choose a table, and then Posey notices the three very familiar — and gorgeous — men sitting near the back. The men send a tray of drinks over to the girls, and Posey realizes that they remind her of the men in her recurring dream.

The next day, the girls head to the clinic, which is located in the old observatory. Posey is starting to get a bad feeling about it all. And they learn that they haven’t just been selected to donate eggs. But to have sex with aliens, get pregnant, and carry the babies.

And Posey signs up.

I have read so many books with this same plot. Or, at least, the first few chapters of so many books. Frankly, I don’t understand why they sell so well. Okay, yes, the books are easy to read and the story pulls you right in. And yes, they are sexy. But other than that…

Get the Kindle ebook free from Amazon here.

2. Grid Down Prepper by Carter Woods

This is a standalone survival book by Carter Woods. This author has been on our Free Friday list before.

From Alex Korolov:

This is an EMP story. That means an electromagnetic pulse wipes out all electronics, affecting cellphones, computers, power grids, and most modern vehicles. Let’s see how this one goes.

Lacey is a bounty hunter in Sacramento who also takes care of her seventeen year-old sister Karen. It turns out both their parents died.

Lacey goes to meet a contact who has some information to offer her. The contact tells her about an antique vase that was stolen a year ago from a museum and is now going up for auction on the dark web. He tells her how she can track it down.

Then we get some background on the relationship, with Lacey and Karen discussing how Lacey is always working. Karen is fine taking care of herself — she just wants to spend more time with her older sister.

Then Lacey goes to a warehouse where she’s been told she can find the stolen vase. Lacey sneaks into the warehouse and recovers the vase. Karen is a little concerned because her contact, who told her where to find the warehouse, also told her something big was coming, like a war or some other crazy thing.

Then the EMP actually hits. Lacey is out in the city, and her car dies, so she has to abandon it. She starts to walk back home to her sister. Of course, her phone is dead, so she has no way to call. Lacey knows things are going to be rough with the EMP hitting, and she calculates that she has a 12-hour walk home.

That’s as far as I got. I like the build up with the first two chapters. I think bounty hunter is a fun job for the protagonist of this type of book to have. Our main character is tough and knows how to get stuff done, which I like. I also like that when the EMP finally hits, the world doesn’t go totally crazy.

Sure, power goes out and people are confused, but it’s not total anarchy yet. Some EMP stories go a little over the top in that direction. This one seems a little more realistic. Anyway, pretty good for an EMP story.

Get the Kindle ebook free from Amazon here.

1.The Amazon Anomaly by Chris Cosmain

This is the first of three books in The Anomaly Trilogy science fiction adventure series. The other books are $0.99 to $4.99 each, and are also on Kindle Unlimited. This is the author’s first time on our Free Friday list.

From Maria Korolov:

I was very — very! — relieved not to see a naked chest on this cover. And I like the font used for the title of the book — very hard sci-fi-ish.

The book starts in 2028, in Brazil, at a logging camp in the Amazon rain forest. Then the forest goes absolutely silent. No bird calls. Then suddenly a cloud of insects swarms the men — giant wasps that sting them until they’re burning in agony. Then the wasps move on and the men pick themselves up, confused, as the welts stop burning. They don’t feel any ill after-effects, so they go back to logging.

Four days later, the men wake up hearing beautiful music and seeing brilliant glowing colors everywhere they look. They walk into the forest in ecstasy to one particular group of trees. They climb the trees, which have strange giant flowers at the tops, and climb into the flowers. The flowers eat them.

Then we go back in time to four years prior, to 2024. We’re still in Brazil, but this time on an airplane. Scarlett, one of the passengers, is having a panic attack, and her neighbors comfort her when they see that she’s in distress. Scarlett takes deep breaths, and one of the other passengers brings her some water.

Finally, the plane approaches Manaus, the seventh-largest city in Brazil, located in the middle of the rainforest, and home to a number of major research institutions. Scarlett is there to give a presentation at an ecology conference. A friend of hers, a biologist studying parasites, meets her at the airport and takes her to the hotel and, after that, to campus, where Scarlett catches up with other scientists.

Then we switch points of view and move to Chile. Karl likes killing people and blowing things up. He’s at a small table with two experienced eco-terrorists. A fourth person joins them, a man who works in security for an agricultural company researching pesticides. He’s provided the terrorists with fake security company identification so they can get in and blow up the research lab. There’s a lot of mutual distrust between the people in this group.

Then we switch points of view again, to New York, where the CEO of one of the largest agri-corporations in the United States, is furious to find out about an illicit research laboratory in South America. He found out about the lab because his intelligence team uncovered a plot, funded by a rival, to attack the lab. It exposes the company to significant risk, so the CEO orders his second-in-command to go down there and shut everything down.

The second-in-command makes plans to save the research so that they can wait and then move on to product development when it is safe.

From the various hints I’m picking up, the search is potentially pretty significant, in an evil genius kind of way.

From the first few chapters, the book reads like a tense techno-thriller, a genre I’m pretty fond of. And it is very readable and well-paced. However, because we switch between so many characters, I’m not really caught up in any one person’s story, and I don’t know whether I’ll stick with it.

Get the Kindle ebook free from Amazon here.


See all the Free Friday posts here. Do you have other free books for us to check out? Comment below or email me at maria@metastellar.com.

Have you read any of these books? Are you planning to? Let us know in the comments!

Or watch Maria discuss all five books in the video below:

YouTube player

MetaStellar editor and publisher Maria Korolov is a science fiction novelist, writing stories set in a future virtual world. And, during the day, she is an award-winning freelance technology journalist who covers artificial intelligence, cybersecurity and enterprise virtual reality. See her Amazon author page here and follow her on Twitter, Facebook, or LinkedIn, and check out her latest videos on the Maria Korolov YouTube channel. Email her at maria@metastellar.com. She is also the editor and publisher of Hypergrid Business, one of the top global sites covering virtual reality.

MetaStellar news editor Alex Korolov is also a freelance technology writer who covers AI, cybersecurity, and enterprise virtual reality. His stories have also been published at CIO magazine, Network World, Data Center Knowledge, and Hypergrid Business. Find him on Twitter at @KorolovAlex and on LinkedIn at Alex Korolov.

Hannah M is a student with a strong interest in publishing. She hopes to build a career that allows her to share diverse stories and voices.

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