SPOILER WARNING: This article contains major spoilers for "American Alien," the Season 4 premiere of Supergirl.
In Supergirl Season 4, Superman is taking some personal time to explore his roots. According to "American Alien," the Season 4 premiere, he left Earth to pay Argo City a visit.
The episode opened with a close-up on a newspaper with a headline that revealed he was no longer on Earth: "Supergirl Is Everywhere! With Superman Off-World, the Girl of Tomorrow Pulls Double Shifts." This kicked off a montage of Kara zooming around the world, saving innocents in National City, Madrid and Kasnia.
Later on, President Olivia Marsdin confirmed Superman's exact whereabouts. "I just wanted to say, with Superman off-world on Argo, your team and Supergirl have been doing a tremendous job keeping this planet safe," she told Director Alex Danvers during a surprise visit to the D.E.O. As revealed last season, Argo City is a Kryptonian city that survived the planet’s destruction.
Though Superman is busy with his vacation in space, fans can expect him back sooner rather than later. Tyler Hoechlin will reprise his role as the Man of Steel for "Elseworlds," this year's three-episode Arrowverse crossover. Additionally, the crossover will introduce Lois Lane, his longtime girlfriend and partner-in-crime.
Airing Sundays at 8 pm ET/PT on The CW, Supergirl stars Melissa Benoist as Kara Danvers, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen, and Chyler Leigh as Alex Danvers.