The song is about a girl (Kagamine Rin) who was given a stuffed teddy bear (BIG AL) as a present to help comfort her at night, the illustrations follow the storyline of the song. The bear keeps the nightmares away and she grows to love and adore him. In return the bear is grateful for her welcoming him to her side.
Later, she meets a boy she falls in love with, but her strict mother is against the idea of her having a boyfriend, so she practices showing her feelings on the bear. The bear takes interest in the boy as it only knows her from the time they spend together. After meeting the boy on what she believed was a date she finally learns that she and he have both mistaken each others feelings towards each other. In a moment of weakness towards her own mistaken feelings, the girl takes her pains out on the bear greatly damaging it in the process. When she realises what she has done to the bear, she regrets her actions, while the bear regrets that he could not protect her from her own mistake.
Without the bear, her nightmares return and she realises how much it meant to her and how fragile the bear was to begin with. Now knowing how much she depended on his comfort while she slept, she repairs him by herself and promises never to let the bear come to harm again.