Bobby must research his family history for a school assignment which leads to more unanswered questions about his fathers real life. Jack and Katie's (guest-star Kate Mara) relationship progresses, while Courtney's comes to a screeching halt after Jack discovers Nate (guest-star Mike Erwin) is cheating on her with another girl. Grace and Tom face the reality of their relationship as she is shocked to learn that her affair with Tom has cost her more then she had bargained for. Jack and Katie play a game to see who knows the other better. Neil Patrick Harris guest-stars as a graduate student in the year 2045.