Series regular Tanya Roberts is conspicuous by her absence during season four of That 70s Show, while Tommy Chong is equally conspicuous by his omnipresence in the role of overaged hippie Leo. It is explained that Roberts character, Midge Pinciotti, has left her husband, Bob (Don Stark), and has filed for divorce; meanwhile, funky Leo pops up at the oddest moments, at one point imaging that he is in love with Kitty Forman (Debra Jo Rupp), mother of the series teenaged protagonist Eric Forman (Topher Grace). The season opens with Eric down in the dumps over his breakup with his girlfriend, Bob and Midges daughter, Donna (Laura Prepon). This plot strand begins harmlessly enough with an extended parody of Its a Wonderful Life, but takes on darker dimensions as the tension between Eric and Donna splits the sympathies of their friends right down the middle. Elsewhere, Erics pal Steve Hyde (Danny Masterson) manages to get back in the good graces of Erics dad, Red (Kurtwood Smith), and moves back in to the Formans basement; Bob Pinciotti tries to get over his shattered marriage by entering into a romance with a woman named Joanne (Mo Gaffney); and hapless exchange student Fez (Wilmer Valderamma) still hasnt lost his virginity. Highlight episodes include Class Picture, in which Eric and his friends flash back to their first meeting, when all of them were second-graders; and the series 100th installment, a tuneful fantasy titled That 70s Musical. In the closing episode of season four, Donna splits with her present boyfriend and runs back to Eric, who feigns indifference. Alas, by the time Eric realizes what a mistake he has made by turning his back on his true love, a tearful Donna has left Wisconsin and is on her way to California. ~ All Movie Guide