Hakushaku-ke wo Mamoru Tame ni Toriaezu Konyakushimashita Neet no Reijou wa Shuubun wo Harashi Ijiwaru na Koushaku-ke ni Taikou suru Tame Ichikabachika no Konyaku wo Ketsuden suru

Marina Adelaide, the daughter of an earl, is living a NEET life after an unfounded scandal is spread about her. Then she suddenly receives the tragic news that the ship her parents were on has gone missing! Although she has a younger brother, he is young and sickly, and if things continue as they are, the Adelaide family will be taken over by the evil Marquis of Lanas. In order to protect her family, she becomes engaged to a stranger, a civil servant named List, but will she be able to stand up to the Marquis's conspiracy? The curtains are now open on a miraculous romance!

(Source: Kodansha, translated)