Madam Secretary will air part one of its milestone 100th episode this Sunday, December 23rd (8:30-9:30 PM, ET/8:00-9:00 PM, PT). “Family Separation: Part 1” will see Elizabeth Adams McCord (Téa Leoni) go head to head with a U.S. governor over the state’s new policy of separating unauthorized immigrants from their children.

Outside of work, Elizabeth will also renew her wedding vows with husband Henry (Tim Daly). Tune in for part one this Sunday and catch episode 100’s thrilling conclusion in part two on Sunday, January 6th (10:00-11:00 PM ET/PT), only on CBS. Check your local listings for more information.