This is a possible concise summary:
Stephen and John pretend to leave the house and sneak back in to prank Grace, who thinks she is home alone. They use a Really Rad Robot to spy on her and record her voice. They find out that she is planning to prank them and that she stole money from Stephen's room. They scare her by ringing the doorbell and hiding behind the couch. Grace freaks out and runs upstairs with a face mask on. Stephen and John reveal themselves and laugh at her. They thank Really Rad Robots for sponsoring the video.
Here are the key facts extracted from the text:
1. John and Stephen are planning to leave the house and be gone all day.
2. Grace will be home alone during this time.
3. They are going to Malibu to get groceries.
4. A taxi is waiting for them outside.
5. Stephen and John plan to use a secret back entrance to return home and surprise Grace.
6. They intend to use a robot, sponsored by Moose Toys, for a prank on Grace.
7. Grace is unaware of the secret back entrance in Beverly Hills homes.
8. Grace plans to prank Stephen and John while she believes she's home alone.
9. Stephen and John successfully sneak back into the house without Grace noticing.
10. They use the robot to record and playback Grace's conversation.
11. Grace mentions planning a prank on Stephen and John during her phone call.
12. Stephen and John continue their prank by hiding inside the house and spying on Grace.
13. Grace steals money from Stephen's room while thinking she's alone.
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