Rheneas has to take slate trucks to the wharf, but when Skarloey has to take coal trucks, even though he needs a rest, Rheneas decides to surprise him and take his trucks to the wharf, too. However, when he comes to the hill he cannot get up with all the trucks, so he leaves Skarloey's in a siding. He delivers the slate, but returns to find the trucks have disappeared. While searching for them, Skarloey appears and says he will have to tell Mr. Percival. Rheneas realises it was all his fault and decides he must tell the other engines. He does and the others support his thoughtfulness, but then Peter Sam arrives with the missing trucks, enquiring as to who was meant to take them. Skarloey and Mr. Percival arrive a few minutes later and Rheneas tells them about his surprise. In the end, everything is sorted out and Skarloey is thankful.