There's a Spaceship in My Tree! by Robert West

Beamer, age 13, who speaks only Californian, is an alien in the world of Middle America, exiled to a bizarre, ancient house on a mysterious street that may or may not exist on any map. With the help of a nerdy African-American kid named Ghoulie, a gangly tomboy named Scilla, and a miraculous, broken-down tree house shaped like a spaceship, he battles the indigenous life forms in his new home, from bullying creatures to the strange inhabitants of dark castles, subterranean caverns, and a spider w