The plan to reclaim Trost falls apart when Eren's newfound powers turn him into a mindless giant. As Titans continue to swarm the city, it's up to Armin and Mikasa to make sure the cadets massacred during the mission haven't died in vain.
After transforming to Titan, Eren seems lost, he is lost in his sleep where he dreams about his childhood days with his family. He forgets his purpose to seal the hole and help the mankind. Mikasa tries to wake him up but fails, when Armin finally succeed by remind him about their promises to go outside the world and destroy the titans.—Sameer Shrestha