LEGO Marvel Avengers: Code Red, on Disney+
Disney Wiki; IMDb; Marvel; On Disney+

Caution: spoilers.

The Avengers fight Red Skull, but because Red Guardian distracts his daughter, Black Widow, by treating her like a child, Skull gets away. However, he's immediately abducted by an unknown enemy. Later, Red Guardian joins the Avengers in a bowling match, and once again distracts Black Widow, making her lose. She gets upset and yells at him. But later, he gets abducted, as well, and she wants to find him. The Avengers figure out that lots of superheroes and villains with "Red" in their name have gone missing, so they go to Red She-Hulk to wait for whoever's abducting them to come for her. It turns out the one responsible for these abductions is the Collector. The Avengers fight his robots and eventually beat them, but Red She-Hulk is captured. So the Avengers get Wolverine to track the Collector to his lair, to rescue all the heroes and villains. And they have quite the battle in store for them there.

That's all I want to say about the plot, except that there's a neat parallel between the Collector wanting to prevent the things he collects from ever changing, and Red Guardian acting like his daughter hasn't changed. Anyway, it's a reasonably amusing special, with a happy ending.