When Subaru Natsuki leaves the convenience store, the last thing he expects is to be wrenched from his everyday life and dropped into a fantasy world. Things aren't looking good for the bewildered teenager; however, not long after his arrival, he is attacked by some thugs. Armed with only a bag of groceries and a now useless cell phone, he is quickly beaten to a pulp. Fortunately, a mysterious beauty named Satella, in hot pursuit after the one who stole her insignia, happens upon Subaru and saves him. In order to thank the honest and kindhearted girl, Subaru offers to help in her search, and later that night, he even finds the whereabouts of that which she seeks. But unbeknownst to them, a much darker force stalks the pair from the shadows, and just minutes after locating the insignia, Subaru and Satella are brutally murdered.
However, Subaru immediately reawakens to a familiar scene—confronted by the same group of thugs, meeting Satella all over again—the enigma deepens as history inexplicably repeats itself.
In the series opening double episode, Natsuki Subaru is summoned to a alternate world on his way home one day. At first, he's enamored with this new fantasy world, but the cute girl summoned him? Nowhere to be found. He quickly learns that he doesn't have any of the powers as a gang surrounds him. Right at that moment, she appears…
After being attacked by someone the first time, sliced open by Elsa the second time, and stabbed in the back by punks the third time, Subaru should have been dead, but found himself back where he started in the same parallel world every time. He finally realizes he's acquired the power to go back to the time and place he started from, which he calls "Return by Death." In hopes of changing the fate awaiting Felt, Satella, Old Man Rom, and himself, Subaru takes off for the fourth time.
Subaru attempts to buy the insignia from Felt and return it to Satella before Elsa arrives at the loot house... but Satella arrives before the negotiations are complete, and Elsa still attacks them.
After being badly wounded by Elsa, Subaru somehow survived and awoke in the mansion of Margrave Mathers, in the Kingdom of Lugunica.
Subaru now lives and works in Roswaal's mansion, working with Ram and Rem, and finally getting Emilia to agree to a date with him. But the day of their promised date never comes as Subaru keeps going back to the day he first awoke in the mansion. He's confused at the thought that he Returned by Death despite having no memory of experiencing anything deadly, but he's determined to repeat his previous actions up to the point of fulfilling his promise with Emilia.
Subaru's first day at the Roswaal mansion begins for the third time. The first time, he grew weak and died of unknown reasons in his sleep, and the second time, he was killed by an attacker. The sound of chains that he heard as he died the second time replays in his mind, waking him in a terrified, cold sweat. He has no idea what the killer is after, let alone who it is, so he makes a plan to leave the mansion on the fourth night and watch for the attack to happen.
Rem knocks Subaru down and tortures him. She suspects that Subaru belongs to a faction against Emilia, and states that he has a smell of witch before killing him. Subaru is revived once again in the mansion, and meets Ram and Rem again, with fear. Emilia worries about him, realizing he is in trouble; Subaru tries to tell her about his deaths and revivals, but just as he begins, a black shadow seemingly with hands overwhelms him. Two days later, Beatrice is sent to see what's bothering him; she also states that he has a strong smell of witch. Subaru asks her to guarantee his safety at the fourth night, which she grants by making a contract with him. On that night, he recalls Rem's attack on him, and feels his hands held by other hands, and then wakes up in Beatrice's room. He gets through the night in this room safely. In the next morning, he walks out of the room, and finds that Rem is dead, leaving Ram in grief. Roswaal states that she died of exhaustion, possibly caused by a curse. He and Emilia ask for clues for Rem's loss, which Subaru is unable to provide. Ram suspects Subaru and tries to attack him, but Beatrice protects him because of the contract. Subaru runs away from the mansion and goes to a cliff. Beatrice approaches him and informs him that the maid twin is incomplete with the loss of one, and offers to help him to escape the territory. Subaru realizes that it was the twin that held his hands in his sleep. Then Ram also arrives, swearing to kill Subaru. Believing that his own cowardice has led to Rem's tragedy, and despite Beatrice's protection, Subaru jumps off the cliff to his death announcing that he will definitely rescue everybody.
Subaru awakens again after being killed, once again. Subaru becomes so intent and focused on getting past this route that he over exerts and exhausts himself, which leads him towards a potential new ending.
Subaru visits the village with Ram and Rem with the purpose of finding the the culprit. When the three return from the village, Roswaal leaves for the night, which did not happen in the previous timelines. Subaru sees Beatrice to confirm that he was cursed and to locate where it was applied to on his body. Having traced the curse to the dog that bit him, Subaru realizes that the children are in danger and that night, he returns to the village with Rem. The children go missing and the two venture into the forest to find all but one of the missing children, who have been bitten by the dog. While Rem heals the children, Subaru goes searching for the last child and gets attacked by a Mabeast. Subaru defeats the Mabeast, but he gets surrounded by a pack of Mabeasts and Rem arrives to clear a path. The two run back to the village, but while buying time to get the children to safety, Rem gets overwhelmed. Rem unleashes the demon within her and goes berserk. With Rem about to be killed, Subaru stands in to take the attack.
Subaru awakens after his battle in the forest with the beasts. He learns from Beatrice that his curse has not been entirely removed. During the battle, the beasts continually cursed him over and over and it is too complicated to remove. After learning this, Rem set off into the forest in order to kill the beasts --can Subaru and Ram get to her before her demon side leaves her too far gone?
In the past, Ram and Rem lived in a demon village where the birth of twins is considered taboo. Ram was a prodigy, while Rem struggled with life. One day, Ram had her horn cut off and Rem had been blaming herself since then. Back in the present, Rem regains her senses after Subaru knocked her unconscious. Subaru, Ram, and Rem run away from the Mabeasts, and they encounter the dog shaman behind the attack. Subaru stays put to fight the shaman, who has transformed into a fearsome beast, in order to let the twins escape. Subaru stabs the shaman with his broken sword, but the attack did no damage. Just before he was about to be attacked, Roswaal arrives to defeat the shaman and the remaining Mabeasts, which removes all of the curses on Subaru. Back at the mansion, Subaru wakes up with Rem in the room, and Subaru tells Rem to keep on living for the future rather than to feel sorry for herself. Subaru goes outside to talk with Emilia and the two agree to go on a date the next day.
At the order of the council of elders that manages Lugunica in the king's absence, Wilhelm and Felix visit Roswaal's mansion as emissaries. Emilia is required in the imperial capital right away, so Subaru asks her to take him along. Emilia tells him this won't be a pleasure trip, but a push from Rem and Roswaal ends in her agreement, so Emilia and Subaru head to the capital. Now all of the candidates to be Lugunica's next king are gathered, and the royal selection is underway.
As Emilia joins Priscilla, Crusch, and Anastasia in a meeting of the royal selection participants, Reinhard enters the hall with Felt. According to a new prophecy seen on the Dragon Stone, there are five priestesses with the potential to be the kingdom's next ruler. Reinhard announces that Felt is the fifth priestess, meaning it's time to formally begin the royal selection, but Felt refuses to have any part in it.
"I just wanted to protect her. That feeling wasn't a lie. Where did I go wrong?" Rejected by the one who meant more to him than anything, Subaru is still unable to recognize that he may have done something irreversible. He then finds out that some disturbing movement has been detected within Roswaal's domain, where Emilia and the others are. He's certain that he can save them somehow, so in spite of Rem and Crusch's opposition, Subaru makes his way back to Emilia...
Upon returning to Roswaal's mansion, Subaru is greeted by an unbelievable sight and wails that this was not what he wanted to happen. Stricken with despair, everything before Subaru starts to go white as, finally, he hears a voice: "You were too late."
Subaru wakes up in front of the appa shop once again. Feeling boxed in on all sides due to his own lack of power to change the situation, he seeks the help of others. First, he seeks the help of Crush, who flatly declines any further involvement passed her contractual obligation of healing Subaru. His requests to Anastasia and Priscilla similarly go unanswered despite his pleas. Having wasted too much time, Subaru decides to at least try to get Emilia away from Roswaal's mansion as early as possible. He then takes a dragon car back home with Rem.
A mysterious figure appears before Subaru and his traveling companions. As the looming beast attacks with a deafening bellow amidst the darkness and fog, Rem determines that it will be too difficult to escape...
Subaru laments that he could not do anything or save anyone, and has no options left. Exhausted, he suddenly takes off running at full speed as if he's made a decision...
To save Emilia, Subaru approaches Crusch to negotiate the formation of an alliance. His terms are a bit difficult for Crusch to believe, but she can see that Subaru isn't lying.
Subaru has devoted everything he had, and done all he could do. His passion has captured Crusch's heart, as well as Anastasia's cooperation, and they all enter into the battle against the White Whale together.
Subaru and Rem are at a loss for words. The battle against the White Whale, which seemed to be going in their favor through attrition, suddenly took on completely different proportions. With their tactical superiority and advantage quickly dwindling, the combined forces all but get tangled up in the threads of despair. That's when Subaru decides to yell out his next move...
With the battle against the White Whale now over, the mercenary force setting up the blockade of the road comes back, Julius at the lead. His arrival gives rise to mixed feelings for Subaru, but after Julius sincerely thanks him for ridding the world of the monster, Subaru finds it in himself to apologize for his past behavior. The group now looks forward, ready to enter the Mathers domain...
The group is making its way in the Mathers domain when suddenly everyone but Subaru disappears and a strange, suffocating atmosphere seeps through the forest. He quickly figures out it is nothing but an illusion, and with help from Julius on the other side, dispels the barrier for everyone caught in it. However, arriving at the village doesn't make convincing the residents to evacuate easy. Time is running out, and the invisible hand of sloth makes its presence at the back of Subaru's mind more and more nefarious.
Subaru devises a new plan to correct the mistake of the blank letter sent to the manor, encourage the evacuation of the villagers and move Emilia away from her current location. With these preparations complete, he enacts the second part of his plan designed to cut off the Fingers before severing the Unseen Hand once and for all.
Emilia is hurriedly ushered to the capital along with the villagers under the orders of a mysterious benefactor while escorted by a rag-tag group of individuals from various and opposing factions. She has but one question on her mind: who could this man be and why would he go so far? Meanwhile, Subaru and Julius face off against the Archbishop of Sin Betelgeuse for the ultimate time. Unfortunately, he is very persistent even beyond death, belying his nature of Sloth. Subaru is relentlessly chased while he catches up to Emilia to save her one last time and answer her question.