Night Kill is a mystery set in fictional Finley Memorial Zoo in Vancouver, Washington, seen from an insider perspective on the challenging and dangerous world of zoo keeping. Iris Oakley, a young zookeeper, hopes to reconcile with her husband after he promises to quit drinking. But he's soon found dead drunk and just plain dead in the lion exhibit. A paralyzing mix of grief and anger at his betrayal keep Iris from questioning the assumptions around his death.

Her co-workers are soon convinced that she is unhinged by losing Rick, but friends inadvertently motivate Iris to prove that her husband could not have died the way it appears. These same friends impede her progress as she follows ambiguous clues and sorts through unlikely motives.

Meantime, Iris must adjust to losing her beloved job as feline keeper and instead learn to be a bird keeper. The veterinarian respects her skills, but the foreman, her boss, would far rather she get a job elsewhere, and the senior bird keeper seems to agree. After Iris survives a series of near-fatal “accidents,” the behavior of a lioness and the death of a penguin at last make clear what happened the night Rick died and who fed him to the lions. Then Iris has to survive to prove it.