Azusa Aizawa, a typical office worker, dies from overwork and is reincarnated in a fantasy world with the condition that she can live forever by killing slimes regularly.
Azusa begins her new life in the fantasy world, killing slimes daily to maintain her immortality and gradually levels up over 300 years.
After 300 years of killing slimes, Azusa finally reaches the maximum level possible, gaining incredible powers and abilities.
To enjoy her eternal life, Azusa builds and opens a cozy inn where she invites various unique creatures and individuals to live and work with her.
Azusa befriends Halkara, a dryad with affinity for nature, who becomes one of her close companions at the inn.
Elulu, a dragon girl, joins Azusa's household, adding to her growing circle of diverse friends.
Laika, a powerful werewolf who runs a pawn shop, becomes a friend and regular visitor to Azusa's inn.
Azusa uses her powers to protect a nearby village from a sudden monster attack, strengthening her reputation in the area.
Azusa and her companions participate in a local festival celebrating peace and friendship among creatures and humans.
