アダール侯国の生き残りであるサクラ姫が異世界より召喚したのは平凡な青年カイ・ワタリ!　だが彼は呪乳(ネクタール)を吸うことで恐るべき戦士へと変身する……!!

Sakura, the last surviving princess of a fallen kingdom, is being hunted down for the power of Ambrosia she possesses – the ability to grant divine strength, but only to a human. With no human companion, she decides to summon one from another world in a desperate attempt to find a knight to protect her, but the man who answers her call is less than what she had hoped for.