Preparation was made for revolt to take place in February 1915. In the first week (of Februaury 1915) he along with Pingle and some other friends went to Agra, Kanpur, Allahabad, Lucknow, Meerut and other places to meet people and consult them about the coming revolt. Finally the day for which they waited so long was drawing near. February 21, 1915 was the day fixed for launching the revolt all over India. All preparations were being made according to that. But at the same time a rat was sitting at the root of the tree of their hopes branches was nibbling at it. Four or five days before (the appointed date) it was suspected that every thing would be ruined because of the betrayal by Kirpal Singh. Because of that suspicion Kartar Singh asked Rash Behari Bose to change the date of the revolt to February 19 instead of 21. Even after doing that Kirpal Singh came to know this. The result of the presence of one traitor within the revolutionary group was dangerous and grave. Ras Behari Bose and Kartar Singh had no real way to keep their plans secret. The misfortune of India can be the only reason for all this.
Kartar Singh reached Ferozepur with his fifty or sixty colleagues according to the place. He met with his friend soldier Havaldar and talked to him about the revolt. But Kirpal Singh had already spoiled everything. Indian soldiers were disarmed. Arrests were made on a mass scale. Havaldar refused to help. Efforts of Kartar Singh were unsuccessful. He went to Lahore disappointed. The pace of arrests all over Punjab was quickened. Friends began to leave them. In this situation Ras Behari Bose lay in a house in Lahore in depression. Kartar Singh too came there and lay down on another cot with his back toward Ras Behari Bose. They did not say a word to each other, but silently understood that agony of each others heart. How can we even imagine what they were going through. "Our destiny remained to hit out heads against the gate. But we could not have the means to try our destiny".
Their only desire was that the way would prolong and they arrived in barrack number 5 near Sargodha and talked about the revolt again. There they were caught. They were chained. Fearless revolutionary Kartar Singh was brought to Lahore (police) Station. He told the police chief there, "Mr. Tomkin, how about some food??" He was so full of life. Friends and foes were equally impressed with his mesmerizing personality - happy to see him. He was happy at the time of his arrest. He often said, "Let me be given a title of revolutionary after I die bravely with courage. Let people remember me as revolutionary Kartar Singh." The trial proceeded. He was only eighteen and a half at that time. He was the youngest defendant. But the judge wrote about him, "he is one of the most dangerous among the defendants. During his stay in America and then in India there is not a single part of this conspiracy in which he has not played an important role."