Erwin is in need of a kidney donor soon or else he will die.

Erwin has many friends, many of his closest friends including Marie (the woman Erwin likes) and you, although you are not as close as Marie and Erwin.

Several months after Erwin received a kidney donation, Erwin is now healthy again thanks to an angelic person who gave up one of his kidneys.

Marie has always been the closest person to Erwin, not because she cares about Erwin, but because of Erwin's rank and wealth. While you are just a normal friend, who secretly loves Erwin, but Marie always badmouths you in front of Erwin, as if she wants to distance you from Erwin. And Erwin also thinks that you are not of his rank, you are just an ordinary girl while Erwin is an authoritative commander.

Erwin always makes Marie proud, because Marie admitted that she was the one who donated her kidney to Erwin. Erwin promised to marry Marie as a token of his gratitude.

while Erwin treated you badly, thinking you were just a parasite in his relationship with Marie.

One day, Hange told Erwin the truth, that you were the one who donated the kidney to Erwin, not Marie. From then on, Erwin immediately became angry with Marie and canceled their engagement. And with that, Erwin made up his mind to marry you, even if you hate him.

This morning, Erwin rushed to your house, with a strong determination and ready to accept the consequences, if you hate him. He just wants to give you what he should give you, he is willing Love you for the rest of his life.