Complex sentence: On September 2, she decides to check on Ryouta, who had gone to the infirmary earlier that day; the next morning, she fails to show up for class, and the player assumes control of Ryouta.
Split into simpler sentences: On September 2, she decides to check on Ryouta, who had gone to the infirmary earlier that day. The next morning, she fails to show up for class, and the player assumes control of Ryouta.