Harley Quinn, on DC Universe (s1-2), HBO Max (s3-5)
Break Room of Geeks (s1) (s2); DC; DC Database; IMDb; TV Tropes; Warner Bros.; Wikia; Wikipedia
other streaming sites: Amazon; Fandango; YouTube

Caution: spoilers.

I've been a fan of the character Harley Quinn ever since she first appeared in Batman: The Animated Series. Of course, this show is much more adult-oriented than that one, with gorier violence, swearing, and adult situations. And Harley (voiced here by Kaley Cuoco) is much more of a badass. I also think the show is pretty hilarious.

The series begins with Harley and the Joker (Alan Tudyk) pulling off a robbery, after which Harley is captured and sent to Arkham Asylum, but the Joker escapes. She expects him to rescue her, but he never does. She's eventually freed by Poison Ivy (Lake Bell), and moves in with her. Ivy's other roommate is a talking plant named Frank. It still takes awhile for Harley to realize the Joker never really loved her, but finally she breaks up with him, changes her costume, and sets herself the goal of joining the Legion of Doom. To that end, she assembles a crew of villains, including Doctor Psycho (Tony Hale), Clayface (Tudyk), and King Shark (Ron Funches). Ivy isn't really part of her crew, but often helps out with their crimes. Ivy and Harley are evicted from their apartment by their cybernetic landlord, Sy Borgman (Jason Alexander), so they go searching for a new lair. But Borgman ends up joining Harley's crew. Ivy begins secretly dating a villain called Kite Man, even though she finds him embarrassing (though she will eventually admit the relationship to Harley and the crew). Harley is eventually inducted into the Legion of Doom, but has a falling out with Ivy. And when Harley temporarily reunites with the Joker, her crew quits. Then Ivy is kidnapped by Scarecrow, so Harley and her crew must reunite to rescue her. Scarecrow enacts his plan to use Ivy's toxins to turn all the trees in Gotham into monsters, so Harley and her crew try to stop him. Then Joker destroys the Hall of Doom with his own giant tower, and apparently kills Ivy. He takes over Gotham, and captures Batman (Diedrich Bader), but eventually grows bored. He plans to execute Harley's crew, but she turns herself over to him in exchange for their lives. Ivy is later resurrected, and rescues Harley, but Joker destroys his tower, setting off an earthquake that destroys Gotham. He falls into a vat of his own acid, which supposedly turns him "normal". And Batman is nowhere to be found. Harley, Ivy, and the crew finally reuinite.

That's pretty much all the most important plot points you need to know about season one, but I've left out a ton of details. The show is really pretty crazy in a lot of ways, but it's a lot of fun. The characters and their relationships to each other are pretty well developed, I think. And the series has an episodic nature combined with a serial nature that works really well. I definitely dig the stories, and look forward to further seasons.