Jim parked a block away from the house and walked down the alley like he had business there. He ended up at his back gate, by the trash cans. He opened the gate quietly and slunk along the side of the garage. When he peeked around he saw Cindy's Toyota sitting next to the back door in the driveway. He quickly got close to it and put his hand on the hood. Still warm. Good, she hadn't been there long. He knew if he went in the back door that it would squeak, so he went to the basement window he'd rigged last night and in seconds he was inside his basement. Now to the stairs, carefully stepping over the third one from the top. It squeaked too. He emerged into the hallway and heard the murmur of voices upstairs. Now he had to use only the sides of the stairs, because most of the ones going up to the second floor made noise. He heard a female's voice. It sounded odd somehow ... full of emotion. By the time he made it all the way up he could hear more clearly. A woman definitely moaned. Was someone hurt? Then he heard Cindy's voice. "That is so hot," she said. Her voice sounded husky ... grown up somehow. It was all coming from Cathy's room. But where was Mark?
There was a groan from the room. A male groan. Heat began to build in Jim's chest. Could the girls have invited the strange male over for fun and games while Daddy was gone? He began to move forward. If that bastard was in there with his prick stuffed in Cathy again, someone was going to die.

Now he was only three feet from the door. It wasn't closed. He could hear movement of some kind in the room. More moans and groans. His face flushed as the heat rose. He thought about just barging in, but thought he'd better get a look at the guy first. If he was too big then he'd go for his pistol and come back.
Very carefully, Jim moved half of his head around the doorframe. One eye looked into Cathy's room. That one eye widened and Jim stopped breathing.

Cathy and Cindy were in the room. They were both naked. Cindy was sitting in a chair facing the bed. Cathy was on that bed, on her back, naked thighs wide spread, and the man was between them. That man's ass was rising and falling between her thighs. He was definitely fucking her.

What had stopped Jim's breath was the fact that the man was Mark.