Conception: Ore no Kodomo o Undekure!

On the day of his high school graduation, right after his friend Mahiru tells Itsuki that she is pregnant, a gate of light transports them both to Granvania, a land where 'Impurities' have brought chaos. In this land exist men whose purpose is to meet with the the twelve Star Maidens to conceive Star Children by pouring energy into a special device. Itsuki is one of those chosen ones.

Conception: Ore no Kodomo o Undekure! is a RPG with Visual Novel elements. The player has to make Itsuki bond with the Star Maidens in order to spawn Star Children who will accompany him into the dungeons and fight the Impurities. The abilities and looks of the Star Children are determined by which character is the mother, and by Itsuki's bond with her.

At the beginning of the game, the player may choose from a selection of names for Itsuki, and select his birthday (Zodiac sign) and Blood Type. The story is then told through conversations reminiscent of Visual Novels, and animations. During the conversations, the player sometimes have to choose what Itsuki says from multiple-choice answers. To travel between the many locations in the world of Granvania, the player simply selects them from a map. Locations where events will trigger are marked as such. Once a party of four Star Children is made, Itsuki can set out to explore the dungeons. The dungeons are made of four parts, one for each season. Only the spring season is available at the beginning. Itsuki and the Star Children then explore, collect various treasures and fight monsters, which are shown on the map. In battle, the Star Children fight as one, acting upon the selected commands. Every turn, once a command is selected for either Itsuki or the Star Children, the player may move them to one of the four sides of an enemy to inflict more damage, or move them to a different enemy. They are rewarded experience at the end of each battle, which will enable them to eventually grow stronger.