Kate's Test is a story of wish fulfilment, in which a miserable girl is gifted the chance to turn her life around. A group of demons offer her the body she's always wanted, in return for her services in generating energy for them. It's a simple exchange but it does have risks. If she overloads the magic crest they give her, she'll lose her humanity and become a succubus, incapable of self-restraint. Kate agrees and is put to sleep to undergo the change, and that's where things start going awry. The sleep program seems to be pushing her into scenarios designed to make her give into temptation and become a succubus. What's going on? What will she do? Will she still be herself when she wakes up. A cute and lewd adventure game with multiple endings.