NBC drama Timeless will wrap with a two-part series finale Thursday, December 20. NBC promises “an epic, unforgettable thrill ride through the past, present and future, with a healthy dose of Christmas spirit.” The second season premiere of the time-travel show started March 11. Eric Kripke, Shawn Ryan and Arika Lisanne Mittman are the executive producers, with Kripke and Ryan creating the show and Mittman running it.