WHILE JACK'S 50TH BIRTHDAY INSPIRES HIM TO RECREATE HAPPY MOMENTS FROM HIS PAST, TRACY DECIDES TO FULFILL A CHILDHOOD DREAM. DENNIS DUFFY RETURNS WITH A HEARTFELT CONFESSION FOR LIZ AND SURPRISINGLY JENNA TOO. — While Jack plans the perfect 50th birthday party for himself he watches old home videos that inspire him to recreate one of the happiest moments he had as a young boy. Liz's ex-boyfriend Dennis "The Beeper King" decides to come clean to Liz about an addiction, stirring up drama between Liz and Jenna. Kenneth and Pete team up to make Tracy's childhood dream come true.