In the world of Type-Moon, it all begins with becoming Morgan's husband!

As a Master who traveled from another world, Ian was not very familiar with Chaldea.
But that's okay, he has a special ability that other Masters don't have—that is, a simulator.
This allowed him to leave his own mark on history.
—It's not quite normal, though.
You became the husband of the enchantress, but at the same time, you cheated on her with the Holy Knight King disguised as a man. Britain is in turmoil because of you.
[You subdued Tamamo-no-Mae and, as her master, showed Minamoto no Yorimitsu what physical exorcism was all about. The demons of the Heian period all gave you a wide berth.]
You have captivated Medusa, and all of Greece echoes with the vow that she will remove her blindfold the moment she reunites with you.
[You are Joan of Arc's soulmate; only you know how to help this usually reserved saint achieve liberation and relaxation in every sense of the word.]
Ian had to admit that this kind of simulator that understands people's hearts was perfect for him.
He solves all problems in his favorite way.
everything is fine.
Until one day, they came to her side as Servants.
Ian then realized that he had gotten himself into quite a few romantic entanglements.