Episode 5 of Sakamoto Days, titled "Source of Strength", features Sakamoto engaging in a fierce, one-on-one fight with Boiled, triggered by a flashback of his assassin days and his desire to protect his family. Meanwhile, Shin and Lu face a challenging battle against Boiled's partner, Obiguro. The episode also sees Nagumo and the special task force "ORDER" investigating a recent string of incidents targeting assassins.
