Charlie offers up breakup advice when Alan admits that his relationship with Donna has become boring and the sex mundane. Alan takes his advice and breaks up with Donna, only to soon learn that she felt the same way about the relationship and wanted to take the relationship to the next level. Alan is relieved until he discovers that Donna meant taking the relationship to the next level by having a threesome.
Meanwhile, Charlie takes Jake to a pizza joint and notices that Jake has been eyeing a girl who is eating pizza with her mom. Charlie unsuccessfully attempts to charm mom into letting Jake come over and meet her daughter. Charlie persists and gets pepper sprayed by the mom, and Jake and the girl have a moment.
The show's 100th episode ("City of Great Racks") aired on October 15, 2007. To celebrate this, a casino-inspired party was held at West Hollywood's Pacific Design Center. Warner Brothers Television also distributed blue Micargi Rover bicycles adorned with the Two and a Half Men logo along with the words 100 Episodes. Each bicycle came with a note saying "You've made us very proud. Here's to a long ride together." The cast also gifted the crew with sterling silver key rings from Tiffany & Co, the key rings were attached to small pendants with 100 and Two and a Half Men inscribed on either side of it.