Ted almost ruins Christmas for everyone when, still carrying around anger toward Lily, he calls her a horribly disgusting name. Robin tends to Barney while he has a cold.

When Ted attends his mother's wedding, he is extremely disturbed by her overly affectionate relationship with her fiancé, which forces him to think about his own life and make an impulsive decision.

When Robin and Loretta's conflict escalates, Barney is caught in the middle. Meanwhile, Marshall and Daphne deal with a stowaway on their road trip, and Ted and Cassie try to enjoy a trip to a lighthouse.