Rise of the G.E.M.S.

by Marian Dealy, Pablo Ballesteros (illustrator)

Don't miss this exhilarating and colorful graphic novel series opener about a group of lab mice who must embrace their newfound superpowers and learn to work as a team, perfect for fans of DOG MAN and INVESTIGATORS!

Theodore, Dorothy, Jonas, Ursula, and Hugh have lived inside a cage their whole lives, cared for by a team of scientists who provided everything they could ever need.

But their lives change overnight when the scientists perform an experiment to transform these five average lab mice into genetically engineered mice. When they’re launched into orbit, the mice learn that the astronauts plan to leave them on the International Space Station—forever. The G.E.M.S. must band together and use their unique mutations to survive in outer space and change their destiny.

Genres: Graphic Novels, Middle Grade, Juvenile

176 pages, Paperback

Published September 23, 2025

About the author

Marian Dealy is an author, filmmaker and award-winning Ph.D. in Biology. Throughout her life, she has gravitated toward the excitement of cutting-edge science. As a young adult, Marian worked as an AIDS researcher at the National Institutes of Health, helped decipher the sequence of human DNA at Human Genome Sciences, then traveled across the country to UC San Diego where she did her thesis project in Genetics. After getting her Ph.D. in Biology, Marian pursued her other passion in life - storytelling. She has worked as a filmmaker for the last 20 years and was inspired by her young son to write books that convey her love of science to the next generation. Marian uses her scientific background to weave the latest and greatest in science and technology into her fictional stories in fun and unexpected ways.

Reviews

[Moth · Rating 5 out of 5]

4.5/5 stars

Thank you NetGalley and Macmillan Children's Publishing Group for the ARC!
Rise of the G.E.M.S. is a cute graphic novel about a group of mice whose DNA gets altered to venture into space. This is the first in a series and ends on a cliffhanger.
This was a super quick, cute read. I had a very fun time reading it, but I did feel like it was a little too quick at times. I was so worried about these mice, and I felt like we never got any solution before moving on to the next conflict.
I would’ve liked to delve more into the characters. We get to know the MC, Theo, really well, but the rest blended together. I also would’ve really liked to read about more of the science-y stuff because the author has a PhD in biology, so I was hoping for more. However, with this being book one in the series, I can understand leaving some room for development.
I’m very excited for the sequel adventure!

CW: animal death; medical content (never shown); abandonment

[Malli (Chapter Malliumpkin) · Rating 3 out of 5]

ARC was provided by NetGalley & Macmillan Children's Publishing Group | Roaring Brook Press


Content/Trigger Warnings: Talk & themes of animal testing


This was a fun, but also highly emotional book for a graphic novel that surrounds animal testing for NASA. I will say, I wish the book had more of the animal experimenting and bigger discussions of animal testing. I fully stand by that being a missed opportunity, but I do understand that the author may have been trying to catering this book more towards younger audiences. There were a lot of times where this book reminded me of the movie The Secret of NIMH. I think if you liked a lot of the elements in this comic, you'll definitely enjoy that movie, but you may want to keep tissues nearby. Overall, this was a fun, fast paced read that addresses a really important topic. I just wish we explored and dove deeper with that topic than what was given to us.



All thoughts, feelings, experiences, and opinions are honest and my own.


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[Jesse · Rating 3 out of 5]

My 9-year-old daughter thought this story was super fun! As soon as she was done she asked me when the second book would come out; a sure sign she enjoyed it! She immediately started reading it aloud to her 5-year-old sister. I enjoyed it less. I wish there’d been more on the ethics of experimenting on living creatures included either in the story or the back matter, but it wasn’t talked about at all.

[Stephanie · Rating 4 out of 5]

Super cute, very quick read. The artwork is fun, the characters have good, unique characteristic’s and personalities. The story is easy to follow and still interesting with themes of STEM without it being boring or bogged down with information. Kids will definitely like it if they’re fans of Catsronauts. And I liked it, it’s giving the secrets of nimh but make it space, with the whole idea of genetically mutated rodents. I’m looking forward to the next in the series!

[Amy Poux · Rating 5 out of 5]

This book is exceptional. The storyline integrated with concepts and super powers are truly brilliant… and there so much opportunity for learning and taking science to new innovative imaginative places. And the illustrations are spectacular, taking visual storytelling to a whole new level of sophistication. I see so many people, young and old alike getting hooked on these G.E.M.S.

[Reader · Rating 5 out of 5]

Such a creative and adventurous way to explore science through the story of a real life experiment through the perspective of genetically engineered mice. The illustrations have a way of sucking you in and making you feel like you are a part of the story. I can’t wait to see what happens next and hope to see a stuffed animal collection for these characters!

[Cathlina Bergman · Rating 3 out of 5]

Just okay: some logical leaps (ex. because a mouse is huge, now she can pilot a spaceship; really? size was the only obstacle?) and some potentially dark elements (ex. mice are left to die in space; one detaches the astronauts and leaves them stranded in space).

[Caitlin Dealy · Rating 5 out of 5]

A very sweet and engaging read! I really appreciated the thoughtful incorporation of science concepts. My three-year-old asks me to read it to her over and over —she loves the illustrations, the storyline, and has already become attached to the characters. We’re definitely excited for the next one!

[Dolores · Rating 4 out of 5]

Genetically mutated mice learn that they are about to be left on the International Space Station--and take matters into their own...paws. Cute start to the series.

[Erika · Rating 5 out of 5]

My 8 year old niece enjoyed the book. She thought it was fun and really liked the illustrations. She can’t wait to read the next one!

[Linda Delaguerra · Rating 5 out of 5]

A quick, fun, yet informative story! My son also loved reading about the unique genetic mutations for each character. The illustrations are captivating, too!

[Reader · Rating 5 out of 5]

What a fun read! My whole family read this book and really enjoyed it!! Looking forward to the next adventure!!!

[Brooke · Rating 3 out of 5]

Thank you to Macmillan Children's Publishing for an eARC of this graphic novel. This is a funny but emotional look at animal testing for NASA. The sentient mice do not get a say in their own genetic modifications, and find out they're going to be left alone in space. What ensues is an escape quest gone awry. I greatly enjoyed what's presented here, but felt like we were cut off mid-introduction. This felt more like a prologue than a true volume one, but maybe that's just me desperately wanting to know what happens next. The art is beautiful and the humor had both my kids cracking up. I'll be interested to see where volume two goes.

[Ali · Rating 5 out of 5]

It’s giving Rats of NIMH with adorable comic style illustrations, and I’m absolutely loving it. Mice leave the lab one-by-one, each returning with a new power from genetic modification: heightened intelligence, spontaneous combustion, growing luxurious hair. And just as they’re figuring it all out, NASA launches them into space. It looks like they’re doomed to be experimented on forevermore at the international space station until the mice...well I'm not going to spoil it but think Rats of NIMH for the space age!!! It is such a perfect, epic twist! Kids are going to devour this fast-paced, empowering story and be clamoring for book 2! I know I am! Highly recommend!!!! ARC read

[Stephanie Rivera · Rating 4 out of 5]

This was a very fun graphic novel about mice who develop super powers and learn how to work together as a team. The illustrations were great and this series is perfect for fans of InvetiGators. I can’t wait to see what happens next and I really liked that the author based these mice on actual mice that were taken to the international space station.
Thanks to Roaring Brook Press and Netgalley for the complimentary copy of this book. All opinions in this review are my own

[Elle · Rating 3 out of 5]

After the story, readers can read about real GEMS and how they are helping scientists in their search for cures to disease, etc.