A face from Lightman's past pulls him into a dangerous criminal conspiracy, testing his friendship and loyalty. Meanwhile, The Lightman Group investigates a high school student's homicidal threats.
Trying to rebound from his recent separation, Walden goes looking for Mrs. Right, while Alan has an opportunity to reconcile with his on-again, off-again girlfriend Lyndsey (guest star COURTNEY THORNE-SMITH).
While Alan struggles to come to terms with Lyndsey's risqué movie past, Walden tries to cheer him up by throwing a party at the house.
Russell (David Spade) finds the unexpected reason behind his negativity towards the holidays. Adam’s (Oliver Hudson) gift for Jennifer (Bianca Kajlich) goes missing and he is forced into some uncomfortable situations in order to get it back. Meanwhile Audrey (Megyn Price) tries too hard to impress the guests at Jeff’s (Patrick Warburton) office holiday party.
Allison is jilted when her new "friend," Sophia (guest star Nadine Valezquez, "My Name Is Earl"), prefers Gary's company over hers.
