Two-on-two basketball is hot and heavy, Marcus and Will vs. T.J. and Andy, when Fiona arrives to pick up Marcus. Marcus wants to stay to help Will win back a large bedazzled belt, which signifies 15 years of competition between Will and his friends. As it turns out, Andy and Laurie are hosting a game night, and since Laurie wants an even number of players, Will's out and Fiona and T.J. are in. Later, Will accuses Andy of letting T.J. steal the belt - was T.J. trying to impress Fiona? Because that could only end in disaster! Will talks himself out of the T.J./Fiona scenario until Fiona knocks on his door, hoping to find a babysitter for game night and sporting a little cleavage. Yes, she dressed up for game night, what of it? When Fiona leaves, Will invites himself to game night - he's got to put an end to this T.J. thing once and for all! Determined Will won't ruin the slight chance Laurie will be happy and have sex with him, Andy agrees to let Will come - but only if he brings a plus one so there's an even number. And no prostitutes!
Later, Marcus trolls through Will's address book looking for the perfect game night date - which is of course, Dr. Sam. Will is just explaining how this relationship requires finesse that no game night possesses, when Dr. Sam picks up the phone. Marcus had already dialed her and moments later the date is on. Unable to find a babysitter, Fiona drops Marcus at the tony home of a new friend, who has three daughters, two of whom, Ashleigh and Megan, look pretty mean. They don't waste any time sending Marcus to the bathroom with their nerdy sister, Katie... which eventually results in his very first kiss!
Fiona moves on to game night, where Andy and Laurie are convinced love is blossoming between her and T.J., disgusting Will, who's determined to be the worst chaperone ever. Turned on, Laurie drags Fiona into the kitchen to advise her to hit T.J.... hard. Since it's time for the games to begin and Dr. Sam hasn't yet arrived, Laurie tries to kick Will out of the house. Instead, he pulls T.J. into the kitchen, where T.J. reveals his intention to hit Fiona later. Hoping to stave off disaster, Will claims he's crushing on Fiona, so T.J. makes it interesting. First one to bag Fiona gets the belt. That's when Will pulls out the big guns: Fiona is the woman he loves.
Insisting on playing charades, for which he's totally unqualified, Will tries to wedge himself between Fiona and T.J., who is cutting a new form in competitive edge. Finally, Will can't stand it anymore. He stops the proceedings to forbid Fiona from sleeping with T.J. When Fiona can't understand why, T.J. explains Will's in love with Fiona... just as Dr. Sam arrives. Laurie is ready to call game night a wash, when a totally desperate Will levels with the room: he's not in love with Fiona, he just doesn't want her to get involved with T.J. because T.J. is not good enough. In fact, Will doesn't want to have sex with Fiona - he wants to have sex with Dr. Sam... but it's not a bag-her-for-the-belt thing at all! As T.J. and Will fall to fisticuffs and Fiona and Dr. Sam huff out, Andy starts guzzling wine, since his chances of getting bagged are over. Game night really is a wash.
Later, Fiona stops by Will's for some words, which he presumes are "thank you" for defending her honor. But all she wants to say is that next time someone wants to have sex with her to win a belt, he should just tell her. And is he looking at her boobs again? Will shuttles Fiona out the door, and when there's another knock, he assumes it's her again, throws open the door and announces yes, he was looking at her boobs. But in fact, it's Dr. Sam, who was touched to learn Will likes her. So she stopped by Andy and Laurie's to pick up the belt - and she's got a first kiss for him too!