S1·E15 A Friend in Need

While Henry visits with his old girlfriend Martha at her farm, Alec spends some time with her asthmatic, mischievious nephew Dennis. When Dennis accidently spooks the Black, he runs away in fear, straight into a grain silo. When Alec tries to chase after the boy, they both end up stuck in the grain silo, which is filling up fast with grain, causing lots of dust that makes it hard for the the boys to breathe. With the help of Pierre and the Black, Alec and Dennis manage to escape the silo relatively unharmed aside from Dennis losing his inhaler and lack of breathing briefly.