Thematic Bible: This plan is thwarted by his nephew

But Paul's sister's son heard of their intended attack, and he went and got into the barracks, and told Paul. And Paul called one of the centurions, and said, "Take this young man to the tribune, for he has something to tell him." So he took him, and brought his to the tribune, and said, "Paul, the prisoner, called me to him, and begged me to bring this young man to you, because he has something to tell you." read more.
And the tribune took him by the hand, and going aside, asked him privately, "What is it that you have to tell me?" "The Jews," he answered, "have agreed to ask you to bring down Paul tomorrow to the Sanhedrin, as though they wish to examine his case in detail. "Now do not let them persuade, for more than forty men are lying in wait for him, who have bound themselves under a curse, not to eat nor drink until they have killed him; even now they are all ready, awaiting your consent." So the tribune sent the young man home with the injunction, "Tell no man that you have given me this information."