Normally when Peter visited Ariel he made sure to do so early in the morning when she still had a bit of energy. Plus he had always thought that by coming to see her earlier. He was allowing her to be able to spend more time with Tristan in the evening.
But that afternoon , Ariel had called him up inviting him to come to the penthouse in the evening for a game of cards. The request itself had been very strange because cards was something that Peter had always beaten Ariel at. She was a very competitive person, so for her to invite him to play a game that she knew her chances of winning were slim. That had put him on edge.
