Ross's lesbian ex-wife, Carol, is pregnant with his child, and he doesn't like her choice of last name for the baby. Rachel finds out that her ex-fiancé went on what would have been their honeymoon with her maid of honor.

The gang searches frantically for Marcel, who slipped out of the apartment while Rachel was baby-sitting him. Just as it looks as though Rachel and Ross might actually spend a romantic evening together, her ex-fiancé barges in and declares his love for her.

Rachel and Barry start dating again, which is kind of awkward since he's now engaged to Mindy, who wants Rachel to be her maid of honor. Meanwhile, Chandler goes nuts when a woman he likes won't return his phone calls.

Rachel agrees to be maid of honor at her ex-fiancé's wedding; she relives the nightmare of her own failed wedding day. Meanwhile, Chandler becomes enamored with a woman he meets on the Internet, but is surprised when he finally meets her. Monica ponders her future with Richard.

Barry and Mindy's impending divorce prompts the gang to fantasize about what their lives might be like if they'd all taken different courses. Ross is still married to Carol, and Rachel is married to Barry, but fawning over famous soap star Joey Tribbiani. Monica is still fat and dating a doctor. Chandler is an aspiring writer and Phoebe is a Wall Street shark for Merrill Lynch.

The gang continue to fantasize about how different their lives could have been. Carol and Ross decide to have a threesome to spice up their marriage. Rachel goes to Joey's but is incredibly nervous about cheating and gets drunk. Meanwhile, Monica's dinner date falls through and Chandler tries to cheer her up but things take an unexpected turn.