Rud is a tank of the Hero's Party and is said to have the highest defense ever in history. The party often does labyrinth raids, but to Rud, it means more than just a raid. To cure his beloved sister's illness, he is in search for the wish-granting treasure that might be hidden in those labyrinths. But one day, the arrogant hero kicks him from the party after an unsuccessful raid attempt, blaming it on his skills whose effects he is still unaware of. Without nowhere else to go and nothing to do, he decides to return to his hometown, where his sister is waiting. On his way there, he saves a girl who was being attacked by a monster. Unexpectedly, this girl has an extremely rare skill called "Appraisal." Thanks to her skill, Rud is able to discover the truth behind his unknown skills, which turn out to be very powerful skills. With a defense of 9999 and powerful skills, thus begins the adventure of the strongest tank, Rud!

When Nashiko Jippensha's mother kicks her out of the house for being too loud, the high school girl needs to find a new place to hang out with her friends. Luckily, Nashiko's father owns a closed-down mahjong parlor that is perfect for her needs. While cleaning out the place, Nashiko discovers a talking bird who introduces himself as a mahjong spirit, encouraging her to try playing the game with her friends. Realizing that they enjoy the game immensely, Nashiko and her friends decide to continue playing and enjoy the new space they have to hang out.

On her 16th birthday, Himari Momochi receives a letter stating she has inherited a mansion called the "Momochi House." Having been raised in an orphanage, this mansion is the only thing left of her real family, so Himari pays no mind to the rumors that it may be haunted. Upon entering it, she meets Aoi Nanamori and his companions, Ise and Yukari, who all seem to be squatting in her new home. Although they warn her to leave the house, Himari vows to be the one to make them leave instead. But soon, she is attacked by youkai and finds out that the house sits in the space between the world of the living and the spirit realm. Even more surprising, Aoi was chosen to be the guardian of the house—a position originally meant for Himari. But this great power came with an awful price: Aoi can never leave the mansion, and his existence in the human world has been erased. Ignoring his pleas for her to leave the mansion, Himari promises to help Aoi break the housebound curse as she begins living under the same roof as him.

Rishe Irmgard Weitzner finds herself in a familiar situation: her fiancé is publicly breaking off their engagement, and her ducal family is about to disown her in shame. However, Rishe is not distraught; she has already had six chances to rebuild her life and chase a different passion each time. But she would always get swept up in a war and die, so now she wishes for her seventh reincarnation to be easygoing and uneventful. What Rishe does not take into account is the presence of Arnold Hein, the crown prince of the Galkhein Kingdom. He is destined to usurp the throne and become a tyrant who starts a large-scale invasion of neighboring countries. To make their encounter worse, Arnold is the one who killed Rishe in her previous life. That is why it is all the more shocking when he proposes to Rishe on the spot. In pursuit of her desired life, Rishe must consider accepting Arnold's proposal and discover the reasons behind his brutal actions to stop the war from ever happening.