The One With the Evil Orthodontist

Rachel has begun an affair with her ex-fiancee Barry, who is now engaged to her former best-friend Mindy. Worsening the situation, Mindy asks Rachel to be her maid of honor, and she also confesses that she had an affair with Barry when he was marrying Rachel. Meanwhile, the gang are unsettled when a stranger across the streets begins watching their every move, which forces Joey to take actions, whilst Chandler becomes obsessive over a women who won't return his calls.