The hippie dropouts at the center of Lauren Groff's new novel, Arcadia, would be easy to laugh at. They make their own soy cheese and bang along to Cat Stevens songs on bongos. They don't believe in personal property and reject pet ownership because they consider it ''slavery.'' But Groff beautifully captures the lives of these deeply flawed ''Free People,'' whose charismatic but spiritually bankrupt guru spearheads a utopian commune in upstate New York. Arcadia unfolds through the eyes of Bit Stone, the son of two of the collective's founders. Bit is 5 when we meet him, and the tribe is similarly wide-eyed and fresh. But then the story jumps forward nine years, and the commune battered by conflicting egos and a swell of clueless newbies starts to disintegrate. Bit, who's never even glimpsed the world beyond his isolated home, suddenly confronts an unfathomable reality: He's about to leave. ''He cannot imagine himself in the Outside,'' Groff writes. ''Because...no matter how he strains his brain, he cannot imagine the greater world at all. He is not ready.''
Bit soon finds himself on an unfamiliar road, terrified by what comes next. And what does happen? Bafflingly, we never find out. There's a huge hole in the middle of Arcadia: Groff jumps ahead 16 years, completely passing over Bit's arrival in mainstream society. The book's remaining pages explore the commune's imprint on a grown-up Bit, his parents, his wife, and others forged in that complicated experiment. It's a sensitive and skillfully written portrait of an eccentric bunch of survivors who are both damaged and sustained by their experience, and Groff spins their stories into a moving look at the value of human connection in a scary, chaotic world. How disappointing, then, that the adult Bit is such an unresolved mystery. B+