Gangster granny

At school (in tuesday), I went to library. After some searching, I found this book called 'Gangster Granny'. It's about a kid named Ben who has parents which are crazy for dance sports and a grandma who loves cabbage and scrabble. He wanted to be a plumber when he grew up, and he read pipe magazines and stuff. Soon, when his grandma went outside, he found out something was suspicious. He found out that his cabbage-loving grandma was a gangster.When his mom asked him for being so sweaty. So, he made an alibi that he practiced dance sports secretly. At his next visit to Grandma's, she told stories about when she was a gangster and stole a bunch of valuable stuff. He found about the Royal gems and decided to steal it. His plan was about she giving the guards chocolate cake mixed with chemicals from sleeping pills. But he couldn't meet with her because the dance sports audition. When he met with grandma, she was waiting for him for 2 hours and 30 minutes.She gave the guards chocolate cake mixed with chemicals from sleeping pills. Then, they went by the river and went up the pipe that Ben saw in his plumbing magazine. Then, they used power drills to make a hole for them to come in. Next, they created an explosion using some stuff. But, they got found by the queen of England. So, grandma told her about how she made up the story that she's a gangster to just have more time with her grandson and how they got here from the top-secured place. The queen let them go. On their way back, grandma told how she lied about her health screening being fine and told that she had a 4th level cancer and she probably won't survive until X-mas. Finally, Ben's grandma died.