There are monsters roaming around in the world and the only way to catch them is through the PSP camera. Install the little device and look at your world in a new light. Catch the monsters with a magic circle, interact with them by patting them.
Of course this is not just about making friends with the dynamic little beasts, you have to train them and level them up. With each new level, the beasts change in appearances, pit them against your friends' tamed pets in battle or tackle story missions.
Project your beast into the real world, onto your work desk, your bed or your bathroom. These pets can go to school or work with you, always have one of them ready for your friends might challenge you for a quick fight on the bus or on the train.