Ep. 4: Between Light and Darkness
Satoshi Hiwatari is a genius child who goes to the same school as Daisuke, and also heads up the investigation to capture Dark. Satoshi suspects that Daisuke is Dark, and when Satoshi discovers Daisuke looking up his Alumnus Profile at school, he decides to test his theory. He sets up a trap that locks him and Daisuke in a chilled storage room, and he sets the locks so that even Daisuke can't break the code! Although Satoshi tries to force Dark to appear, Daisuke resists, and eventually Satoshi loses his composure and Krad, Dark’s enemy and “other self”, appears. Daisuke calls Dark and a battle ensues, with neither side winning. After the fight, Satoshi decides to leave school for a while to keep his distance from Daisuke. (Source: D.N.Angel Wiki)