As Mason goes in for his six-month check-up, Kourtney realizes that she wants to have another baby so her kids will be close in age, like her and Kim. But when Kourtney becomes obsessed with getting pregnant, Scott feels that she's taking all the fun out of the process, leading to struggles getting intimate in the bedroom. Meanwhile, tensions arise between Bruce and 12-year-old Kylie when she breaks the rules by inviting a boy up to her room. Bruce has a hard time accepting that Kylie has male friends, while Kylie thinks her dad is being too overprotective. But when Kylie runs away without telling her parents, will Bruce realize he may have come down too hard on her?