孕ませレジェンド召喚！絶対零度の爆乳姫騎士を肉オナホにする成り上がり異世界性活

The protagonist is a servant serving in a certain temple.

One day, using a rare treasure called "Ticket", a ritual is held to summon the great heroes. But during the ritual, an evil spirit Giselle, attacks the place. The protagonist, who is peeking in on the ritual, also gets caught up in the commotion.

Rather than getting killed, the protagonist uses the Ticket, and is able to summon the best and rarest being from the spiritual world whom he has been longing for, the princess knight Rufina. After defeating Giselle and settling the situation, Rufina challenges the protagonist to a match to see if he is qualify to be her master.