A Long Day in Dunwall is the first mission in Dishonored 2.
Emily Kaldwin gazes at the sky above Dunwall Tower before being led into the throne room by Alexi Mayhew. Corvo Attano joins Emily and they each lay a rose for Jessamine while discussing the anniversary, Emily's worries about being Empress, and the Crown Killer.
Emily sits down on her throne, and City Watch Captain Mortimer Ramsey announces that the Duke of Serkonos, Luca Abele is visiting. The Duke enters with two Clockwork Soldiers and his Grand Guard, who carry an enclosed chair into the room. He introduces his gift as 'the lost sister of Jessamine Kaldwin', naming her Delilah Kaldwin; Delilah steps out of the chair. She accuses Corvo of being the Crown Killer and declares herself the rightful Empress. As the crowd reacts in shock, the Duke's soldiers slaughter them. Three traitorous City Watch guards surround Emily with swords drawn, while the few loyal guards are killed by the Clockwork Soldiers. Corvo defends Emily; raising his covered hand, he kills the three traitors in an instant, before he blinks up to Delilah and stabs her. Delilah, unharmed, ensnares Corvo with her own magic, and removes Corvo's sword from her chest before she removes Corvo's mark from his hand. As Emily tries to come to Corvo's aid, Ramsey attempts to restrain her, but he releases her after she punches him.
As Delilah releases Corvo, Emily helps Corvo up, and the two stand back to back, both unarmed and surrounded by guards. At this point, the player is prompted to choose whether to play as Emily or as Corvo.
Once either character is chosen, the game continues from that character's perspective. Delilah will petrify the character that was not chosen, turning them into a marble statue, while Ramsey stomps on the protagonist, rendering them unconscious. He tells Delilah and the Duke that they will be held in Emily's Imperial Chambers, then brought to Coldridge Prison to await trial.
As Ramsey carries the protagonist to Emily's room, Mayhew appears, unaware of Ramsey's betrayal. While Mayhew asks Emily or Corvo what happened, Ramsey stabs Mayhew with Corvo's folding blade. He leaves the blade with Mayhew's bleeding body, and continues dragging the protagonist to the Chambers. He tells them about the (entirely true) legend of the Imperial Safe Room, said to contain 'enough gold to buy a good-sized island' and steals their Imperial signet ring, intending to use it as a key to open the Safe Room. He leaves, locking the protagonist in the Chambers.
The protagonist can open the windows from inside Emily's Chambers, allowing them to climb out onto the ledge, where they can escape to an adjacent room, in which Mayhew is found. Mayhew tells the protagonist to escape via the Safe Room to the Dreadful Wale, giving them Corvo's sword before dying from her previous injury. The protagonist must make their way back to the throne room, and there can either kill Ramsey or take/follow him to the Imperial Safe Room and lock him in there.
Reaching the Dreadful Wale
After leaving Dunwall Tower via the Safe Room's other door, the protagonist must make their way from Dunwall's rooftops to the ground level, near the city armory. From there, they can either ride a train carriage, skipping most of this part of the mission, or work their way along the ground and through the buildings to the docks. Once there, the protagonist must swim to the Dreadful Wale and talk to Meagan Foster, the captain of the Dreadful Wale, to end the mission.
- Time Capsule – Found a room boarded up since the time of the Rat Plague.
- Freedom of the Press – Protected the printer of the Dunwall Courier newspaper from Duke Luca Abele's agents.
- Jessamine's Words – Re-played an old audiograph message from Empress Jessamine Kaldwin.
- Coin of the Realm – Took what gold you could carry from the Dunwall Tower Safe Room reserves.
- Dr. Galvani's Safe – Robbed the safe of Doctor Galvani, a Natural Philosopher from the time of the Rat Plague.
- The Ramsey Fortune – Locked Mortimer Ramsey in the Safe Room with a fortune in gold, and a month's worth of food and water.
- The code for Galvani's safe, the first safe the player can find, is 451, which was also the code to the first safe in Dishonored. This continues a trend from System Shock and Deus Ex, among other games.
- The original opening of Dishonored 2 was longer and started with the launch ceremony of the ISS Jessamine Kaldwin, Emily exploring the city's rooftops and facing the Crown Killer herself. It then opened on the throne room scene and the coup.
- The non-lethal elimination option for this mission is the only one that can be un-completed without murder. Opening the door to the Imperial Safe Room after closing it with Ramsey inside removes the tick from the objectives list.
- Attempting to leave the Safe Room via the exit door before picking up the nearby equipment will instead pick up said equipment. The door must be interacted with a second time to be used if that was the case.