In the case of Apocalypse, the story arch is "The Supergirl from Krypton" and it not only features the origin story of Kara (Superman's cousin), AKA Supergirl, but it also pits the heroes against one of the biggest enemies in the DC Universe, Darkseid.
While the events of the previous film lead up to Apocalypse, it isn't really necessary to have seen Public Enemies prior to this film. This is mostly due to a news reporter recapping all of the necessary information just as the film starts. Here, we are reminded of the raining Kryptonite chunks and the events that lead up to them falling from the sky. When an unusually large block falls in a Gotham river, Batman investigates only to find the pieces of Superman's home also contained a ship. As it turns out, Clark isn't the only survivor of Krypton, and his young cousin has been hurtling through space for many years, and Batman has just woken her up.
Kara has immediate trouble fitting into human life. With only minimal control of her powers, Superman has her staying at the Fortress of Solitude, but when she gets cabin fever, she decides to head out on her own. When she once again loses control, Superman agrees to let her go to Wonder Woman's Paradise Island to be trained.
Meanwhile, on the planet Apocalypse, Darkseid is looking for a replacement leader-Fury since his former leader, Big Bertha, has left the planet and hidden away on Earth. When Darkseid learns of a Kryptonian female living on Earth, he decides to make her his new enforcer. Of course, his minions will have to get through Superman, Batman and Wonder Woman on Paradise Island to do so. Superman/Batman: Apocalypse has a good helping of fights, including two against Darkseid himself, and another against a swarm of Doomsdays. On top of that, the voice-acting continues to be top notch with Kevin Conroy and Tim Daly reprising their roles as Superman and Batman respectively. The deep-voiced Andre Braugher takes up the role of Darkseid, while Summer Glau plays Kara and Susan Eisenberg reprises the role of Wonder Woman that she held during the Justice Leage animated series. The voice actor I found most amusing though was Ed Asner as Darkseid's right-hand woman and advisor, Granny Goodness.
The great voice-acting coupled with the same artwork style from the series in high definition really makes the movie impressive. Add to that the great selection of special features, and Superman/Batman: Apocalypse becomes a must-own for anyone who is a DC fan.
Superman/Batman: Apocalypse not only comes with a pretty good animated short featuring the Green Arrow and a few of his friends and foes, but also a slew of featurettes on the New Gods and Supergirl, as well as four episodes from Superman: The Animated Series that fit perfectly in this disc.
The four episodes include both parts of "Little Girl Lost" and "Apokolips Now!" - the first one being the introduction of Supergirl to the series, and the second one being a major battle between Superman and Darkseid. As for the featurettes, three of them focus on not only Darkseid's origins, but the origins of his family, the New Gods. This includes discussions about Highfather, Darkseid's altruistic opposite, and their sons. The last featurette is all about Kara and not only talks about how the character changed over the years, but also interviews several people who played her in her various incarnations, including Smallville's Laura Vandervoort.
Like I said above, if you are a DC fan, then Apocalypse won't disappoint, and if you've already picked up Public Enemies, then this film does a great job of following up the story and characters.