Ellie's best friend is now into volleyball and doesn't have time for her. When Ellie finds out from her flakey babysitter that her Mom will be late because her grandpa was at the police station, Ellie has no clue what is going on. Then her mom shows up with a teenage version of her grandpa and she's even more confused. Her Grandpa Melvin has managed to reverse the aging process by using a jellyfish that has the ability to regenerate itself. When he tests it on himself and becomes a teenager he is arrested in his lab for trespassing because no one recognizes his younger version. Gramps is desperate to get back to his lab and retrieve his research and with the help of Ellie and her new friend, Raj, the three have all sorts of adventures.
Jennifer Holm's characters are out there and memorable. Gramps only wants Chinese food for dinner and his fashion sense is either old man clothes or he raids Ellie's mom's closet. When he wears her black leggings I did cringe. Ew! Raj has the Goth look going with a hieroglyphic earring and black garb. Ellie's character arc involves her discovering that she really likes science and questioning when science goes too far and actually hurts humanity. The message of not giving up and new beginnings swim in and out of the plot. Marie Curie and Oppenheimer are discussed as support for these themes.
The title and cover of this book are clever. Just like Ellie's goldfish that never died, her Gramps is the fourteenth goldfish. And the beaker with the partial jellyfish floating off the page show how experimenting with science has made what seems impossible, possible. Then there is Holm's great lines. Here's a favorite of when her Gramps was complaining about aging: "'They stick you away in nursing homes and assisted-living facilities just because you're old.' Kind of like middle school. [Ellie thinks.]" An undertow of humor will propel you through this book.