Since the last episode, Diane has been coming in late to work at Cheers. The cause for this is that she has given into the request for artist Phillip Semenko to paint her portrait.
During their sessions, Phillip can't help but take verbal jibes at Sam, with Diane defending him every step of the way. However, as he nears the end of painting her, Phillip finds that he has trouble finding the intense emotional anguish within Diane that inspired him to paint her. Diane's talk again turns to Sam, and as she continues to analyze their relationship, the anguish returns, and Phillip finishes his painting.
Now that his work is completed, Phillip takes leave of Diane. Like before, he cautions her again that if she shows Sam the painting, they will part. Like before, Diane rebukes this, claiming the painting will allow Sam to understand why she did what she did.
When she returns to the bar, all the patrons are attending a picnic that Coach has put on, except for Carla who is tending the bar. Diane takes Carla's place, and when Sam appears, she reveals the paper-wrapped painting that Phillip did. She is eager to show Sam, but he is still upset that she did something he told her not to.
Alone in the bar, the two begin to delve into their feelings, which soon devolves into Sam letting out his animosity towards Diane regarding her attitude towards him, and her attitude towards many things. Eventually, the two get into a small quarrel, before Sam tells Diane to "get the hell out."
Diane warns Sam that this will surely be the end of their relationship, but he does not back down. As she walks out the door, he almost goes after her, but retreats to the other side of the bar. On the stairs outside, we see Diane's feet stop on the stairs, turns back towards the bar's entrance...before turning around, and continuing up the steps.
A few moments later, Sam finally takes the paper off Phillips painting, and looks at it for a few moments, before uttering one word: "Wow."