When a pizza deliveryman mistakenly gives Natalie $50 in extra change, Natalie decides to do a good deed. She follows him, intending to return the money, but is shocked to find his car on a deserted street, with the deliveryman beaten to death in the driver's seat. Stottlemeyer and Disher arrive to assess the situation, but they're soon called away to a bigger case. With the authorities distracted, Natalie feels obligated to champion the cause of the dead deliveryman. She goes to Monk for help, but he's feeling sick, and soon finds himself stuck in bed with the flu. Natalie is now on a mission to get to the bottom of things.