Complex sentence: Thalia needs antibiotics for the injuries she sustained, and Clarke discovers that they have been stolen from the pods, leading Bellamy to discover that Octavia is the culprit, who reveals that she became a drug addict during her incarceration.
Split into simpler sentences: Thalia needs antibiotics for the injuries she sustained, and Clarke discovers that they have been stolen from the pods. When he confronts her, she tells him that she became a drug addict during her incarceration.