When will Supergirl season 4 return to The CW? This year's "Elseworlds" crossover event is essentially an interruption to the regular series, dropping most of the ongoing plots in each show in favor of a worlds-colliding narrative in which John Deegan uses the Book of Destiny to wreak havoc. When the dust settles from this epic, the various CW superhero shows will go on their Christmas breaks, to return next year.

That means the traditional Supergirl mid-season finale was really "Bunker Hill," which aired on December 2. That episode saw a number of arcs build to a head, with the D.E.O. successfully discovering Agent Liberty's true identity and bringing him in. Unfortunately, that victory has secretly backfired; the arrest has given the Children of Liberty a massive propaganda coup, while a public accusation has forced Supergirl to quit the D.E.O. rather than go public about her secret identity.

Related: Supergirl: 7 Big Questions From The Season 4 Midseason Finale

Supergirl has always considered itself to be very much politically aware, but season 4 has pushed it further than ever before. National City is serving as an extended metaphor for contemporary American society, with anti-alien prejudice acting as a mirror for current race relations in the United States. It will be fascinating to see how the series brings these plots to a close.

When Supergirl Season 4 Returns In 2019

Supergirl season 4 will return to The CW on Sunday, January 20, at 8pm ET. The show switched to Tuesday night for the "Elseworlds" crossover, but is now back to its regular Sunday night slot. Ominously, the next half-season will begin with an episode titled "Secrets and Lies," suggesting that the conspiracy that began with the President Marsdin's outing of an alien will continue (that phrase is often associated with political deception). At this stage, though, it's far too soon for the release of an official synopsis.

What To Expect From Supergirl Season 4 Part 2

Supergirl season 4 currently has a lot of plates spinning at once. There's been a lot of speculation that President Baker is secretly in league with the Children of Liberty, and that he's really prejudiced against aliens himself. That would certainly explain why he put Haley in charge of the D.E.O.; she evidently doesn't view protecting aliens from hatred as a priority for her organization. It will be interesting to see how the new, arm's-length relationship between Supergirl and Haley's D.E.O. plays out. It's quite possible Haley will object to an alien vigilante flying around the city without any accountability. Meanwhile, Kara herself will suffer from the loss of the D.E.O.'s support and technology. Poor Alex may find herself in a very difficult situation indeed, with her loyalties divided between her sister and her job.

The arrest of Agent Liberty may well prove to be a Pyrrhic victory. Lockwood's angry retorts have already cost Supergirl her job with the D.E.O., and he's sure to take every opportunity to air his anti-alien rhetoric. To his followers, Lockwood will be viewed as nothing more than a martyr, and the bruises on his face when he was arrested are a PR disaster for the D.E.O.. President Baker had already hinted that Agent Liberty could well walk, and now his identity is public knowledge he'll be a far more dangerous force to be reckoned with. Meanwhile, even as tensions build between Kara and the US Government, the Russian Supergirl is sure to become an important character. She's largely been forgotten so far, but the showrunners have claimed Supergirl season 4 will be partly inspired by the classic Superman: Red Son storyline. That suggests the doppelganger is a clone who has been recruited and trained as a weapon by the Russian government, which is sure to add even more pressure to the relationship between the real Supergirl and the D.E.O..

Of course, the real question is just how Lex Luthor fits into all this. Jon Cryer has signed up to play Superman's greatest nemesis in Supergirl season 4, and he's set to appear towards the end of the season. At this stage, it's impossible to say for certain what Luthor's role will be; there's been some speculation that he's the real architect of the various anti-alien movements that have been seen in Supergirl to date, but only time will tell whether that theory is correct.

More: Supergirl Theory: Lex Luthor Has Been The Villain Since Season 1

Supergirl season 4 will return to CW on Sunday, January 20, at 8pm ET.