What's on TV Tonight | October 1
How I Met Your Mother 7-7:30pm, CBS. As Barney prepares a pre-nup, it causes his friends to consider making contracts with their significant others.
The Mob Doctor 8-9pm, FOX. As Grace treats the victims of a hit-and-run, Constantine advises her to focus on the driver who caused the accident.
Major Crimes 8-9pm, TNT. When an old case of his is overturned, Tao questions his prior actions.
Castle 9-10pm, ABC. Castle and Beckett attempt to hide their relationship with co-workers as they return to work to investigate the death of a weathercaster.