Beloved author Rachel Vail's newest series, about an earnest young dinosaur who tries as hard as he can, and his frazzled mother who always knows how to save the day.

Mama Rex and T are two dinosaurs living in the city. T, a young dinosaur, is just like any other kid -- he stays up late, he messes up his room, he gets in trouble, and he loves his mom. And Mama Rex is just like any other single working mom -- she drinks lots of coffee, she's always running late, and she loves T more than anything else in the whole world. T's friend Walter is coming over, and T is ready for a day of fun! But this play date doesn't turn out the way T expected. Walter gets too rambunctious -- and T just gets fed up. Can Mama Rex fix the most horrible play date in history?