Fastening Days 4(2019)

Fastening Days 4 is an animated series where Yoji, Kei, Kelly, and the bear-shaped robot Oscar defend their town using Fastening Machines. When a shy transfer student named Samhen joins their class alongside his talkative AI companion Jack, the group discovers an unexpected friendship. As the two newcomers integrate into their circle, a sudden threat emerges that puts the entire town in danger. The heroes must work together to protect everyone while exploring the deepening bond between humans and artificial intelligence. The series balances action and heart, examining how connection and teamwork—especially between people and machines—can overcome any crisis.