Casey decides to move to Paris with her boorish boyfriend. In an effort to make her stay in Denver, the guys flip a coin to determine which one of them will propose to her.
Riley and McCusky feel like wimps when Casey chases a burglar from their home - and then starts dating a macho cop.
Casey is upset when her housemates decline to accompany her on their annual vacation. McCusky has met the woman of his dreams in a bar, but spilled his drink on the name and number she gave him and knows only that ""her name has an F in it."" Riley has been fired from his newspaper job - because all the well researched and written obituaries he printed were for people not actually dead yet - and invests his severance pay in an ostrich pair for breeding purposes, which proceed to terrorize the household.
When McCusky encourages his sister to become a nun, his roommates tempt her.
Casey has her work cut out for her when she's promoted to district attorney - and hires Riley as her new secretary. Meanwhile, McCusky is dating an uninhibited female doctor.
Casey and McCusky worry that Riley may want a sex change after he buys a girl's bike and, having been wheeled unconscious into McCusky's emergency room is spotted wearing red ladies' panties (which he borrowed from Casey because he had no clean underwear).
A truly terrible smell takes the trio into the basement, where they discover a dead turtle in a shoebox—and become trapped when the door blows shut. After they discover and consume a cache of cheap wine, Riley drunkenly blurts out a terrible secret: that he and Casey once slept together, violating their pact that the trio would remain just friends forever. An explanatory flashback takes them to the day of their senior prom, when Riley was dumped by his girlfriend hours before the event and Casey found out that her gentlemanly boyfriend became a beast after hours.