Arc 2 of Re:Zero Life in a Different World from Zero also known as The Tumultuous Week is the second arc in the series which follows Subaru as he recovers from his harrowing first day in a new world. It is covered in Volume 2 and 3 of the light novel series, spans from episodes 4 to 11 of the anime, and volumes 3 to 6 of the manga (collectively known as Dainishou).

Previous: Arc 1 - A Day in the Capital
Next: Arc 3 - Return to the Capital City

Synopsis

Waking Up in a Mansion

Subaru wakes up in the Mathers mansion where he was brought after being stabilized by Emilia. He meets the other residents of the mansion - Roswaal the owner, Ram and Rem the twin maids, and Beatrice the guardian of the library. He learns that the entire royal family died recently and mysteriously from the same illness. Emilia is currently a candidate to become the 42nd King of Lugnica. Roswaal offers Subaru anything within his power for saving her life and he asks to be a butler in the mansion.
He begins to dutifully learn the basic skills of mansion upkeep from the twin maids. While still an anomaly Subaru gains the trust of the twin maids and it seems that he'll settle into this new world and new life but after going to bed on the 4th day he finds himself waking up on the morning of the first day he arrived at the mansion. He quickly works out that he somehow died in his sleep and resolves to repeat the past timeline as closely as possible and survive the 4th night and figure out the cause of his death.

Another Loop

Subaru attempts to repeat the events of the past loop as closely as possible and once more asks to be hired as a butler in the mansion. However, inexplicably to him everyone reacts slightly differently this time around and Ram even volunteers to teach him reading and writing in the evenings as he lacks the ability to do so in the new world's language. Soon enough the night of the 4th day arrives and he braces for whatever happens to him at night. As the morning drew on he began to feel ill and realized that he was somehow under attack. He left his room fearing for the other residents in the mansion but before he can warn anyone he is mercilessly killed by an unseen assailant.

Information Gathering

He awakens once more on the morning of his first day at the mansion. This time Subaru opts to stay as a guest instead of a butler. His aim is to gather information wherever possible and to be outside of the mansion so that he can get a better idea for the attacker's plan. He still practices his literacy skills but on the 4th day he leaves the mansion on the pretense of setting out on a journey. In truth he camps at a cliff overlooking the mansion and waits with a kitchen knife he stole from the mansion.
As the sun begins to set he is suddenly attacked. Rem wielding a morning star on a chain chases him down and cripples him. She begins questioning him and his motives. She tortures him by hurting him with her monstrous strength and then healing him so he doesn't die. Subaru begins to realize that she thinks he is a spy (especially in this timeline with his shady behaviour posing as a guest that left the mansion to watch it) for another party interested in the Royal Selection. Since he is not he has no answers to give her and eventually he is killed by an unseen force.

Giving Up

Subaru wakes up again and is beginning to feel desperate. He tries to tell Emilia about his Return by Death ability but a dark presence threatens to crush his heart if he does so. He all but gives up and begs Beatrice for help. She promises to protect him and he actually survives to see the morning of the 5th day which he thought was impossible at this point. However, his inaction somehow meant that Rem had died instead of him. After some serious soul searching he realised that he really wanted to do everything in his power to protect the people of the mansion. Steeling his resolve he commits suicide by jumping off a cliff.

The Final Pieces

Subaru begins the week anew with the goal of earning the trust of the mansion members and figuring out the cause of his death in the first place. While working as a butler he solicited advice and information from Beatrice. He figures out that he was cursed and that it required physical contact. He realizes that the only place he could have been cursed was when he visited the nearby Irlam village in his past lives. He uses himself as bait and Beatrice confirms that he was cursed when he was bitten by a stray dog. He has finally solved the mystery of his death and even managed to avert it, but he begins to fear for the children who also played with the puppy.

Wolgarms in the Woods

Sure enough the children in the village are missing. Subaru and Rem take off into the dangerous forest area to rescue them. While every child is saved, the duo are hurt while trying to escape. Rem reveals that she is an oni but even so Subaru gets badly hurt. He survives until the next day but Beatrice informs him that he has multiple layers of curses placed upon him, that she cannot undo them, and that Rem has gone back into the forest to kill the Demon Beasts before they activate the curses and kill him.
Fearing for Rem's safety Subaru and Ram go in after her. The three eventually group up but have incurred a fair amount of injuries by this point. Subaru makes a move to distract the pack of beasts to buy time for the sisters to escape. He puts up a valiant effort but is about to be overwhelmed and killed when Roswaal swoops in from the sky and saves all of them. The remaining Demon Beasts are exterminated, the wards around the woods are restored, and the entire incident is resolved.

Links

Fan Wiki
MyAnimeList
List of Re:Zero Anime Episodes
List of Re:Zero Volumes