Grey’s Anatomy

ABC | 8:00 pm

Now in its 15th season, "Grey’s Anatomy" hits another milestone with its 332nd episode, "We Didn’t Start the Fire," which makes this Shonda Rhimes blockbuster the longest-running medical drama in television history. The story finds Jackson (Jesse Williams) throwing a party to celebrate Catherine’s (guest star Debbie Allen) surgery and thank everyone who helped save her, but virtually nothing goes according to his plan. Elsewhere, Alex and Jo (Justin Chambers, Camilla Luddington) get a visit from Helen (guest star Lindsay Wagner).