Elvis Martini is in deep shit. His dilapidated Detroit apartment building is about to be foreclosed on by the bank; most of his tenants are behind on rent; he's in big debt to bookies and his daughter's school. He finds some ill-gotten cash in an evicted tenant's apartment and it briefly keeps the wolves at bay, but it brings out a bigger wolf, one that wants his stolen money back. When his daughter is kidnapped by the mysterious menace he's accidentally messed with, Elvis has 24 hours to come up with $25K - cash only.

Their relationship on the rocks, a young Brooklyn couple heads to a remote B&B to work things out. But from the moment they arrive at The Happy House it's one disaster after another, and they soon begin to suspect they've wandered into a real life horror movie. Events escalate from weird to terrifying as they contend with the house's batty owner, her imposing son, a moody Swedish lepidopterist, a pedantic English professor, an extraordinarily rare butterfly, the world's best blueberry muffins, a .44 Magnum, a demented serial killer, and one very strict rulebook.