Exit

By Belinda Bauer. (Atlantic Monthly Press, 336 pages, $26.)

Belinda Bauer's mystery is surprising, mordantly funny and it has a happy ending. For what more could you ask?

Charming characterizations, maybe? It has those, too. Felix Pink is a sardonic pensioner who only realizes he has been coasting through life when he bumps up against what might be a murder. Calvin Bridger is a lonesome, not very ambitious constable who prefers dealing with friendly crimes until he finds himself on the trail of a killer. It's their behavior that propels the plot and inspires most of the comedy in Bauer's book.

She's great at twists and, unlike some contemporary mystery writers who whip from one unlikely development to the next (looking at you, Alice Feeney), Bauer has a gift for connecting the novel's sudden shifts to the unpredictable foibles of humans.

It's best not to say too much about the plot, which is put in motion when Felix volunteers for a shadowy organization that promotes euthanasia, but if this is your first Bauer, there's even more good news: She has eight other crime novels and the final pages of this one all but promise an "Exit" sequel.