As the 12th Doctor’s time aboard the TARDIS comes to a close, so does Doctor Who showrunner Steven Moffat’s tenure at the helm. Peter Capaldi and Moffat will both be leaving the show at the close of Season 10, and the upcoming departure clearly has Moffat pondering his seven-year Who legacy. His magnum opus? The fate of River Song.

“I vaguely thought I’d be going last year,” Moffat says in an interview with Empire Magazine, talking about 2015 series of the show. “So the last scene of Christmas that year [during the "The Husbands of River Song"] with the Doctor finally making it to Darillium, which we hear about in the episode just before I took over, was as close as I’ll ever get to making any attempt at closure.”

“The Husbands of River Song,” 2015’s Doctor Who Christmas Special, finally gave closure to the fan-favorite River Song’s journey. Season 4’s “Forest of the Dead,” written by Moffat, marks the Doctor’s first time meeting River and her subsequent death. “The Husbands of River Song” brings her story full circle.

Despite the end of Season 9 being Moffat’s legacy in his mind, he’s still got one more season to run before he leaves, so there’s a good chance something else will become his legacy in the near future when Doctor Who Season 10 premieres April 15.

Photos via Doctor Who Wiki