Attack on Titan: Chronicle is the series' fourth compilation movie, retelling the first three seasons of the Attack on Titan series based on the manga by Hajime Isayama.
Overview: In the fourth compilation movie, episodes 1-59 of the anime are retold, compiling the first three seasons of the anime into one two hour event.
Summary: In the year 845, over one hundred years after the appearance of the Titans, humanity receives a grim reminder of the threat that the Titans pose. Under the belief that they were safe behind the Walls, a Colossal Titan peers over Wall Maria and breaks Shiganshina District's outer gate. Eren Jaeger rushes back to his house along with Mikasa Ackermann to rescue his mother, Carla Jaeger, who the two children find trapped under debris.
Source: Attack on Titan: Chronicle, available under CC BY-SA 3.0.