Wolves and dogs not a part of Thunder Pack are unable to gain the power of the storm naturally, but spiritually. Angelwing, being the current Beta Female of Thunder Pack, needs to have the power of the storm to lead. Since she's a dog and wasn't born in Thunder Pack, she travels to soft cliff with Bluemoon to gain it. Jumping into the sky, trusting the spirits around her, she's struck by lightning and soon claims the power of the storm.