Torn From The Sky [Supernatural]

Sam and Dean are just coming in from a tiring hunt, when they hear a sound like an atomic bomb going off. They go to investigate but Castiel pulls them away trying to protect them. The trio soon discovers the barely breathing body of a young male angel that cannot speak at all. A few days later, after the young angel has been properly fed and cared for by Castiel and the two brothers, the body of another angel crash lands into a field they were driving past. This angel is a girl this time, and it turns out they knew each other back in Heaven. So why have they suddenly been ripped from their home in the clouds?