The castle's first protection was a small set of walls that now are almost destroyed. After them, a pentagonal shaped wall surrounds all the structure. These walls had square-shaped battlements over them. When the Scouts arrived, at least two of the five walls are completely broken.
Inside the walls, there was an empty courtyard with a small stable, two doors that communicated the interior part of the castle with the exterior and a stair that communicated the ground with the walls and the base of the towers.
The towers were the most prominent feature. They were the tallest part of the castle and connected by a small bridge. One of them was broader and taller than the other, and had the same battlement that the pentagonal walls do. The other was thinner and smaller, and its top part was destroyed when the Scout Regiment found it.
The castle is first discovered when two squads from the Scouts come across each other while searching for the breach in Wall Rose. The decision is made to take refuge within the nearby castle, and rest until morning before resuming their patrol. The group includes senior members Nanaba, Gelgar, Henning, and Lynne as well as several rookie members under their command - Bertholdt Hoover, Reiner Braun, Conny Springer, Christa Lenz and Ymir.
Inside, the Scouts find evidence that the castle had been recently occupied, with several crates full of contraband suggesting it had been used as a bandit hideout. The group gathers in an intact room, and attempt to get some rest while things are quiet. However, the mystery of the intact Wall and Conny's village come up, creating an argument where Ymir mocks him in an attempt to distract him from the issue. The senior officers set up a watch on top of the tower, and prepare for a long night.
Two hours later, Ymir sneaks away to search for food. She is found by Reiner, and they share a brief discussion until Ymir finds and identifies a can of herring, written in an unknown writing. Reiner picks up on her ability to understand the writing, but before he could confront her, the castle comes under attack by Titans able to function normally during night. As the group gather on top of the tower, they spot the Beast Titan walking past the castle and heading for Wall Rose.
The senior Scouts leap into battle, maneuvering using the tower to combat the wave of Titans. A group of smaller Titans break into the tower, and are combated by the rookies, who successfully immobilize them from advancing up by blockading a passage, at the cost of Reiner's arm being seriously fractured.
Lynne, Henning and the horses are all killed when the Beast Titan, having climbed up Wall Rose, hurls several chunks of the wall at the castle. It then summons a second, larger wave of Titans to assault Utgard. Nanaba and Gelgar continue engaging the Titans, with a scarcity of gas and blades, until Gelgar, having hit his head, falls down towards the Titans. Nanaba manages to save him, but her gas runs out and she is left stranded. With this, both veterans are devoured by the Titan horde. Stranded and without a weapon, the recruits are left helpless atop the tower, unable to do anything but prepare to die.
However, at dawn, Ymir makes the decision to reveal herself as a power of the Titans user and jumps off the tower, transforming to fight the other Titans. Ymir begins attacking the Titans, ripping out their napes with her powerful jaw, whilst the other cadets can only look from atop the tower in shock. The tower is badly damaged in the fight, yet Ymir still does her best to protect it, at risk to her own life. Christa, however, convinces her to tear the tower down instead, and whilst it is collapsing, Ymir rescues the other recruits. The Titans are buried by the rubble, but begin to reemerge and overwhelm Ymir, nearly completely devouring her. Just before a Titan could eat Christa, Hange Zoë's squad arrives and begins executing all of the remaining Titans.
In the aftermath, Ymir lays in the rubble, near unconsciousness in human form. As the Scouts look on, and before Ymir passes out, Christa reveals her true name is "Historia." With this, the recruits are rescued from the collapsed Utgard, and return to Wall Rose.
- In Norse mythology, Utgard is the stronghold of the Giants.