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.
Thalia needs antibiotics for the injuries. She sustained the injuries. They have been stolen from the pods. They was leading Bellamy to discover that Octavia is the culprit. Clarke discovers this. She became a drug addict during her incarceration. This is what the culprit reveals.