The story follows Shin, a young adventurer who, despite being a seventh-rank adventurer, spends his days cleaning toilets. This unusual choice of work stems from his desire to be thanked for his actions, a sentiment born from a past life where he felt unappreciated. He was once Sanada Shinichi, a high school student who died in an accident. Upon his death, he encountered a celestial being named Jill, who explained that his past lives were filled with unfulfilled potential and a lack of gratitude, leading to a massive debt of "karma points." To repay this debt, Shin was reincarnated into a world of swords and magic, tasked with earning points by performing good deeds and receiving genuine gratitude.
Shin's current life as an adventurer is marked by his unique approach to quests. He actively seeks out jobs that allow him to help others, even if they are menial, like toilet cleaning, because the clients express their gratitude. This contrasts with the typical adventurer's pursuit of monster subjugation for rewards and status. His altruism and unusual methods have earned him nicknames like "Flower Picker Shin" from other adventurers, who view him as cowardly or effeminate for avoiding direct combat and focusing on civic duties. However, Shin's true strength is revealed when provoked; he possesses incredible speed and combat prowess, capable of easily defeating much stronger opponents. He uses these skills defensively, often to protect himself or to recover costs incurred from helping others, as seen when he incapacitates bullies who demand money.
Shin's motivation to earn gratitude extends beyond his current life. He frequently visits an orphanage, donating money and even hosting a barbecue party with rare monster meat. He also helps a young boy named Max and his mother, Ririsa, who suffers from a magical deficiency. Shin provides them with medicine and food, refusing monetary compensation but insisting on their sincere thanks. He also maintains a cordial, albeit verbally sparring, relationship with a gruff but kind-hearted old pharmacist who provides the medicine.
His past life as Shinichi is revealed through flashbacks. After his death, he was informed by Jill that his previous ten lives were largely unproductive, accumulating a massive debt of karma points. He was given a chance to reincarnate in a new world, but his debt meant he would be reborn as lower-ranked creatures until it was repaid. His first reincarnation was as a parasite, a "tapeworm," due to his massive debt and Jill's initial failure to properly imprint his memories. Through a complex celestial bureaucracy and the intervention of a higher-ranking being named Cecilia, Shin was given a second chance to reincarnate as a human in the world of "Zildogard," but with a significantly higher burden of earning karma points. He is now a seventh-rank adventurer, working to repay his debt by accumulating gratitude, with Jill acting as his invisible, often food-obsessed, spiritual guide and support.
In Zildogard, Shin's primary goal is to earn enough karma points to clear his debt and avoid further undesirable reincarnations. He works as an adventurer, taking on quests that allow him to help people and earn their gratitude. He also uses his skills to protect those weaker than him, like Max and Ririsa, and even helps other adventurers when their lives are in danger, provided they express genuine thanks. His interactions with other adventurers, guild staff, and the people he helps reveal his underlying desire for recognition and appreciation, a stark contrast to his past life's lack of it. The narrative highlights the contrast between Shin's perceived weakness and his hidden strength, his unusual motivations, and the complex system of karma and reincarnation that governs his existence.
