Can you give a summary of the story "jaque mate en dos jugadas" by isaac aisemberg

There are two boys, one of them is Guillermo, the other one is the narrator, Claudio Alvarez... And they live with their uncle. The uncle is a rich guy, but he is very strict, for instance, he doesn't like Guillermo's girlfriend because she's not enough for him. And he wanted the other boy to be a biochemist... So both boys really disliked their uncle.. One day Claudio and his uncle started playing chess everyday, according to the uncle, the boy was good at chess... Anyways, one day Claudio got tired of his uncle and decides to poison him, he planed everything very well, according to him.. The boy goes to a bar the same day he gave the poison to his uncle, he was waiting for the poison to do its work , as the boy was in the bar he started feeling a little bad about what he had done. When he comes back home, he finds the cops.. and the cops started questioning him, and they were asking him tough questions, so at the end the boy feels forced to confess, so he says " all right, i did it, i did it, i got tired of my uncle" When the inspector heard his confession, he wasn't surprised at all, and proceded to ask him, "well, since you already confessed, tells us where's the revolver?" and of course, the boy was surprised.. so he says " what revolver? and the inspector says " stop pretending, i'm taking about the revolver you used to kill your uncle" and that's the end of the story! it seems like the boy it's gonna go to jail even though he never used any revolver, but he confessed