There's an outbreak of chicken pox in the air courtesy of Ross' baby son and Phoebe is the unfortunate recipient - just as her estranged naval boyfriend (guest star Charlie Sheen) is due in town for a fortnight. Monica and Richard discuss their compatability when her OCD goes to some strange lengths with regards to the way the bedsheets should be folded, and Chandler hires Joey as a favour but soon starts to regret it when Joey begins making life difficult for his new boss.