When it wrecked us: Season three, episode 19 ("Just Say Yo")
Why it wrecked us: Will struggles to balance school, work, and his social life, so a classmate gives him speed to help him stay alert in the days leading up to prom. Will keeps the drugs in his locker, but on the night of the dance, Carlton takes the amphetamines, thinking they're vitamins. He ends up overdosing, which lands him in the hospital. At home, Will breaks down and admits that Carlton got the drugs from his locker. He apologises and becomes emotional, realising that if Carlton died, it would've been his fault.