In episode 75 of Mahabharata aired on 27th December 2013, Vidura learns about Duryodhan's plan of killing the Pandavas and Kunti
Vidura tells the detective to keep a watch on Karna and inform him about his activities. Kunti, Yudhishthir, Bheem, Nakul and Sahdev reach Varnavat. Purochan lies to them about the palace. Kunti, Yudhishthir, Bheem, Nakul and Sahdev enter the palace. Kunti asks Purochan to keep the lamp in front of the door. The detective informs Vidura about Karna. Vidura learns about Duryodhan's plan of killing the Pandavas and Kunti, and decides to inform about the same to Bhishma.
Vidura tells the detective to keep a watch on Karna and inform him about his activities. Kunti, Yudhishthir, Bheem, Nakul and Sahdev reach Varnavat. Purochan lies to them about the palace. Kunti, Yudhishthir, Bheem, Nakul and Sahdev enter the palace. Kunti asks Purochan to keep the lamp in front of the door. The detective informs Vidura about Karna. Vidura learns about Duryodhan's plan of killing the Pandavas and Kunti, and decides to inform about the same to Bhishma.