Complex sentence: Noriko witnesses Oki attack Shuya and after the 2 fall down the hill she runs after them and finds Shogo Kawada has saved Shuya Kyochi Motobuchi after which Kawada teams up with them.
Split into simpler sentences: Noriko witnesses Oki attack Shuya and after the two fall down the hill. She runs after them and finds Shogo Kawada has saved Shuya Kyochi Motobuchi after which Kawada teams up with them.