At first, Peter's sort of a wishy-washy Charlie Brown. He doesn't think he's good at anything and considers himself sort of a "lone wolf." Though he's older than Anne, he exhibits a good deal of immaturity—he's shy and doesn't know how to deal with girls. He easily falls prey to Anne's pranks and can't really stand her.
All this changes when he sees Anne "stand up" to the grownups. He starts to realize Anne's a pretty courageous gal and someone he might like to get to know better. He invites Anne up to his room for some teenage chats and they are both relieved to have someone to talk to. Their friendship begins to turn into a bit of a romance (Peter pecks Anne on the cheek—oo la la!), but before either one can consider what's really happening the annex residents are arrested.