Johnny is a successful banker who lives happily in a San Francisco townhouse with his fiancée, Lisa. One day, inexplicably, she gets bored of him and decides to seduce Johnny's best friend, Mark. From there, nothing will be the same again. In San Francisco, we follow Johnny, a man who has a girlfriend, Lisa, and also his best friend, Mark. Lisa has been cheating on Johnny with Mark and Johnny doesn't know! Will Johnny ever find out? Will Mark still be Johnny's best friend?