Andrew, Duffy, Andrews Mom, Aunt Elise, and Marie are going to a house one weekend in October and they go back home to get Duffy's suitcase and they lost an hour.
Everyone helped to clean the house when they got there because it needed fumigating. Next, they went to bed because they were tired. Then, they woke up and looked around the house, and they found a Beware of the Sentinel sign.
The kids went to the woods and it was cold at first. Eventually, it got hot, so they took their coats off. When they got back to the house, Duffy realized he forgot his jacket.
After they got back from the woods Andrew's mom got mad then Aunt Elise and Andrew's mom went to the store to get lightbulbs since only two worked. After they left the kids were playing Monopoly and they heard knocking and scratching on the door.
The kids got scared and when Duffy looked outside and saw a big creature and they all went outside to the barn but when they tried to open the door it was locked. They all went back inside and went into the bedroom to hide.
The sentinel got inside because the front door was unlocked and he went upstairs to the room the kids were hiding in. He returned Duffy's jacket and ever since then Duffy didn't need someone to remind him for almost a year.