Hi, I'm looking to book a ticket for a train departing on Sunday from Cambridge please? What is your destination? I want to arrive at London Kings Cross. What time would you like to leave by? It is a 51 minute trip for 18.88 pounds. I don't have a departure time but I want to arrive by 21:30. There is a train leaving Cambridge on Sunday at 19:00. It arrives at London Kings Cross at 19:51. May I book that for you?