Pinky and Brain are genetically enhanced laboratory mice who reside in a cage in the Acme Labs research facility. Brain is self-centered and scheming; Pinky is good-natured but feebleminded. In each episode, Brain devises a new plan to take over the world, which ultimately ends in failure, usually due to Pinky's idiocy, the impossibility of Brain's plan, Brain's own arrogance, or just circumstances beyond their control.

An elite team of medical experts of the National Institutes of Health investigates unusual public-health crises, such as sudden outbreaks of serious and mysterious diseases.