Arriving home from a date with Ronee, Martin sneaks up behind Frasier and yells, “Boo!” Although Frasier knows Martin enjoys practical jokes, he doesn’t appreciate being surprised that way. The next day, following Frasier’s private session with Mimi, a pediatric nurse trying to overcome her crippling fear of clowns, Martin stops by Frasier’s office and “spooks” him again.

Frasier decides to teach Martin a lesson. As part of Mimi’s treatment program, Frasier has acquired a full clown costume and makeup. One night, he tells Martin he’s going out, but slips back into the apartment to don the clown gear. Frasier rings the doorbell, and when Martin answers, Frasier pops out and surprises him. To Frasier’s dismay, the sudden shock causes Martin to collapse.

In the emergency room, Frasier neglects to tell Niles that he caused Martin’s heart attack until a nurse blows his cover by reading the paramedics’ report aloud. Fortunately, the doctor terms Martin’s collapse a “mild cardiac event” and sends him home the next morning. Initially, Martin refuses to tell Ronee about the incident, fearing she’ll view him as an old man. But later, Martin not only ‘fesses up – he proposes to her.