There’s a box in Dongwoo’s room. One day, Dongwoo’s mom said that

she was going to throw it out but Dongwoo refused. Dongwoo’s mom 

asked why and he said that it has the debt that he has to pay for his

whole life. Inside, there’s the receipts of what Dongwoo’s parents have

bought for him and a paper written with every little thing that his

parents have done for him. Dongwoo’s mom cried after that.