Eleven-year-old Ellie has never liked change. She misses fifth grade. She misses her old best friend. She even misses her dearly departed goldfish. Then one day a strange boy shows up. He's bossy. He's cranky. And weirdly enough . . . he looks a lot like Ellie's grandfather, a scientist who's always been slightly obsessed with immortality. Could this gawky teenager really be Grandpa Melvin? Has he finally found the secret to eternal youth?

With a lighthearted touch and plenty of humor, Jennifer Holm celebrates the wonder of science and explores fascinating questions about life and death, family and friendship, immortality . . . and possibility. Look for EXCLUSIVE NEW MATERIAL in the paperback--including Ellie's gallery of scientists and other STEM-appropriate features.

And don't miss the much-anticipated sequel, The Third Mushroom

"Warm, witty, and wise." --The New York Times

* "Written in a clean, crisp style, with lively dialogue and wit, this highly accessible novel will find a ready audience." --Booklist, Starred

* "Top-notch middle-grade fiction." --Publishers Weekly, Starred

* "Ellie's memorable journey into the world of science will inspire readers to explore the world around them and celebrate the possible." --Shelf Awareness, Starred

"Awesomely strange and startlingly true-to-life. It makes you wonder what's possible." --Rebecca Stead, Newbery Medal-winning author of When You Reach Me

25 STATE AWARD LISTS including the Sunshine State