Synopsis

The lights inside the train flickered, and Heon was suddenly alone, saved from a dead body missing an arm and a mysterious cloaked man.

He was trapped in the train running circle. A loop without a stop.

The mysterious cloaked man proposed a deal. He would stop the train for Heon, but only after retrieving a missing key in the other realm.

Accepting it, Heon woke up with a newly-attached black hand formerly belonged to the dead body on the train. He was teleported to a world of magic and sword. One where the most powerful king was murdered, and the blood-thirsty queen hunted for the assassin.

Unfortunately, he found drawings of his face plastered all over the city.
Wanted:
Dead or Alive.
Heon Lightwalker - the Kingslayer.

At least, he got Sunny; an alleged murderer slash healer mage, and Azran; a bounty hunter who now stuck by his side due to unwanted association with him. Hopefully, they could survive the kingdom-wide manhunt.

But, how would he find the key to fulfill his deal, when the key was going to be used to release the Great End?

Was exchanging a key to his own real world equal to ending this parallel one?