Ross leaves Rachel in charge of 'monkey-sitting' Marcel, but he escapes when Rachel isn't looking. Animal Control gets called in, but since Marcel is an illegal pet, things get ugly between Rachel and the Animal Control officer - a woman named Louisa who Rachel was mean to in high school.

An routine day filled with ordinary traumas becomes nightmarish when a distracted Mark critically misdiagnoses a pregnant woman's delivery complication. A teenager is brought in after being accidentally poisoned. Benton grapples with his own demons in the wake of his mother's collapse.