Speculative in almost every way. Ghosts? Got em. Aliens? Most Definitely. Creature of lore? Absolutely.
Two main protagonists, Amy (a mixed species girl from a family with a past) and Jack (her wolf-mutant best friend), and their adventures, though the story scope goes far beyond just these two in side-stories and branch-offs.
Time travel, dimensional hopping, and much more.
"There's always something new to find or explore, especially when I'm bored." - Amy, probably at some point.
[The best way I can explain it is that it is similar to DC comics or Marvel comics with an overarching universe with many timelines, characters, and so on that, all intersected in different storylines and character arcs.]