S5, E20: When Hank Hooper (Ken Howard) threatens to cancel "TGS", Jack (Alec Baldwin) convinces him to allow Liz and company the chance to do their 100th episode. To produce the best show possible, however, Liz must deal with less-than-ideal working conditions. Amidst the chaos of show preparation, Jack starts doubting a key decision in his life and Jenna (Jane Krakowski) contemplates motherhood. Part 1 of 2.