According to Wikipedia
Loki, the Norse god of mischief, has been exiled to the human world by the god Odin for reasons that he doesn’t understand. Along with being exiled, Loki is forced to take the form of a human child, and the only way he can return to the realm of the gods is by collecting the evil auras which take over human hearts. In order to do this, he starts a detective agency which specializes in the paranormal. Loki is assisted by his loyal companion Yamino and the pair are soon joined by a human girl named Mayura Daidouji who is manic for mysteries and often unwittingly assists him in catching the auras. As time passes, however, other Norse gods and characters appear, some of whom befriend Loki and others of whom are intent on assassinating him.
If your familiar to the Marvel series about Thor and Loki… Completely forget about them, as this anime series from 2003. Turns even the legends you know about these characters and makes it their own. What you get in this series is striking visuals, amazing animation, and stories the likes of which you hadn’t seen before. All I can say is that you like the trailer, you will love the series. It is that good and even better.