Ellie and Melvin are back in this followup to The Fourteenth Goldfish. Melvin has been on the road for the past year and tired of it. He is also tired of "the puberty". So he and Ellie team up for the science fair. They have an axolotl that seems to have extra appendages so they feed bits of it to fruit flies to see what happens. Of course Melvin also experiments on himself. 

Ellie is also dealing with the fact that her mom has remarried and her budding feelings for her best friend Raj. Should they become more than friends? When her cat Jonas gets sick, she and Melvin try to revive him with the axolotl to no avail. But is the axolotl having an affect on Melvin? 

It was wonderful to revisit these characters. Melvin was just as awesome as the first time around and I truly enjoyed his budding romance with the school librarian and his angst about the puberty. I thought Ellie's situations were extremely realistic with maybe having feelings for a boy friend and resuming her friendship with an old friend. Things change in middle school. The part that really got me was the death of Jonas since I just recently went through the very same thing with my cat. That part seemed extremely realistic to me.