永久不滅デビルポイント

Nanjou Fusato feels pretty worthless, with no friends, no girlfriend, and (from his perspective) no strengths. One day, he tries to summon a demon using a ritual he found in a book at a weird curio shop. The summoning works, after a fashion, and he soon has a friendly rookie devil companion named Selphie; however, instead of granting his every desire, she can only grant wishes that he has the "devil points" for, as listed in a handy catalog. When Fusato runs out of devil points, he will die. Will he be able to get out of this tricky situation?