Wizards nation manga

Wizards Nation summary:

From: Shinnen There are rumors of a grand treasure located within the local museum of Ashiwara and that this treasure requires a special key to unlock. But no one seems to know what this treasure is or even what the key looks like. But Kei and Hikaru, two childhood friends, may inadvertently find out when someone seeks to claim the treasure for themselves and that action plunges their world into chaos.