[@AcetheKidd], but here; a simple explanation.

[b]Digimon: Counting Stars[/b]

Eight children from different parts of the world. Eight sets of dreams that would summon them to a luxury beach resort in the Philippines. Eight tickets that would allow them to enjoy access to the resort and all the fun it promised. Then, a blackout in which a gateway into a world different from what they once knew opened without warning, a gateway into the realm known as the Digital World. For champions are needed against a great evil, a threat that seeks to take over all universes, Human and Digital both.

It is a shame that it is the threat itself that has realized this, and seeks to recruit said champions for their own ends.

A brief explanation. In the 1940s, the Atanasoff-Berry Computer and ENIAC were invented, one after the other. They created the first Digital World, the one we know today as the world of [i]Digimon Adventure[/i]*. After them came the various Yggdrassil units, supercomputers who implanted themselves into countless parallel universes, creating Digital Worlds in each of them as well. A few of these Yggdrassil units were benevolent, some were arrogant and tyrannical, but a few were merely devoted to esoteric goals and agendas.

The local Yggdrasil merely wished to find others like himself, yet this goal was already enough to do damage, as in order to breach the walls between universes, said local Yggdrasil had to bust a hole in the Digital World; this would kill those inhabitants who cannot get to safety. Seven of the most powerful Digimon objected to that not just because their homes were threatened, but because they wanted Yggdrasil's power for themselves. 

These Seven Digimon, later known as the Seven Demon Lords/Seven Deadly Sins, attacked Yggdrasil as the latter were about to begin his plan, and killed him. They then took over the Digital World, replacing Yggdrasil's destructive neglect with their own destructive malice. 

Dorumon the leader of Yggdrasil's elite guard, the Royal Knights, decided to resurrect him by recruiting eight human children to partner with several Digimon, who would overthrow the Seven Deadly Sins and then use the power of their crests to revive Yggdrasil...who would be free to burst open holes in the Digital World once more in an attempt to contact his siblings as well as Atanasoff and ENIAC. Note that he does not plan on telling you this; some secrets are best kept hidden.

So, yes, a morally grey tale where you choose between willful evil and wanton destruction, [i]unless[/i] you figure things out and come up with your own solution...

*This is Canon, by the way, see [url=http://syldra.net/yesterday/eniacabc.html]this link[/url]. And yes, they were Canon Characters before Yggdrassil was a thing.