Smart move

Jon came back to his bedroom with the drinks and find no one. He immediately find that something is wrong and put his drinks on the table. He checked under a lath of his floor and find his stone. He then put it back and look under his pillow and see the fake stone he made just before isn't there.
And Jon smile at his genius idea to makes a wish that he had a second stone who fullfil small wishes but turn against his owner when it become more serious. He didn't know how Sarah find out about his stone but she will have a big surprise soon...