You can download it from iTunes here.

Manufacturer description:

"Son of Asgard features stunning HD graphics optimized for Retina Displays that bring Asgard and Thor to life. Step into the role of Thor in this epic 3D action game. Asgard is under siege from forces both inside and outside its walls. Wield the great hammer Mjolnir as you battle rampaging foes to protect the kingdom and the nine worlds. "