After a near-collision rattles their wheels, Percy and Kana enlist the help of Emily to introduce new safety measures all over Sodor. However, their anxiousness about accidents push Percy and Kana to ridiculous extremes that only makes more trouble! When Percy has another accident caused by his off-the-rails safety obsession, he refuses to leave Tidmouth Sheds. When he has to leap into action to help his friends, Percy learns that paying attention to your surroundings is the best way to not have an accident.