When it comes to anime films that tie-in to ongoing shonen series, generally they tend to not be canonical – and basically exist to show a whole bunch of additional cool fights. My Hero Academia: Two Heroes is basically that, except with the nice addition of showing a little bit more of All Might’s backstory, through the introduction of an old friend from his earlier career.
My Hero Academia: Two Heroes is set prior to season 3, during summer vacation. All Might has taken Midoriya to I-Island, a man-made island home to a variety of super-science think-tanks. The island is due to be the site of a Stark-Expo-esque confrence, with one of the presenters being David Shield, a friend of All Might from his college days, and who designed the fabric in All Might’s costumes, in addition to the style of the costumes themselves.
The rest of the members of Class 1-A are themselves present in various capacities, from Todoroki being present on behalf of this father, Bakugo being there based on his performance in the sports festival, and Mineta and Kirishima are working as wait staff as a part-time job. The supporting character for the gang is Melissa Shield, David Shield’s daughter who is a little older than Deku, and has some teased romantic tension which basically goes nowhere.
However, a group of highly equipped villains take over the expo and take the attendees hostage, with the members of Class 1-A slipping under the radar, allowing them to try to make their way through the building to restore the security system and release All Might and the various heroes in the building, to save the day.
If the response to that synopsis is “Boy, that sounds a lot like Die Hard!” You’re not wrong. Melissa even spends a not insigifnicant chunk of the movie barefoot after dumping her high heels (though nobody has to contend with a room full of broken glass or a constant search for replacement shoes).
Is it as good of a Christmas movie as Die Hard? No. However, narratively My Hero Academia: Two Heroes works – we get a nice glimpse at All Might’s earlier career, and it’s interesting seeing some of the members of Class 1-A thrive in a Die Hard scenario. Probably my one complaint with the movie is that one of the characters I’d have liked to see showcased in the film – Froppy – gets very little screen time. Indeed, a spot in the movie that could have really showcased her abilities instead has freaking Mineta get the spotlight instead.
Still, if you enjoy My Hero Academia, and just want to see these characters go, and to see All Might still let a Detroit Smash or two loose, this is a good movie to go with.