Positopia World: The Hidden Portal - Linda J. Cronin - Bog

Jack is just like most other kids. He loves riding his bike and making mud pies. Jack also has an engine that can turn green, yellow, or red. When he is very upset his engine is red; when he has settled down a bit, or is nervous or worried, his engine is yellow; and when he is calm and happy, his engine is green. Sometimes, Jack has trouble controlling how he reacts to his engine. One day, while playing in the backyard, Jack accidentally opens a portal into another world. Positopia World is full of amazing colors, stunning landscapes, and talking animals. The adorable woodland creatures help Jack learn how to bring his engine back into the green. But when he starts to miss his family, Jack decides it's time to go home. The problem is, the only portal back is on the other side of the dark and scary Midnight Forest...