In criminal law, conspiracy is a planning (agreement) between two or more people to commit a crime on a future date. 

Section 120A of the Indian Penal Code, 1860 (IPC) defines criminal conspiracy as when two or more people agree to do or cause to have done an illegal act or an act which is not illegal but done through illegal ways is designated as criminal conspiracy. Here, it is immaterial whether the ultimate object of the agreement is illegal or an incidental act to the agreement is illegal. 

Section 120B of the IPC mentions the punishment to the criminal conspiracy which ranges from rigorous imprisonment to imprisonment for life/ death.

IPC makes conspiracy punishable only under two formats i.e., conspiracy by the way of abatement and conspiracy involved in certain offences such as thug, robbery, etc. 

Merely having a discussion or having knowledge about any ill intentions that one has does not amount to a criminal conspiracy. It is essential for the combination of elements as defined for the offence to be framed. Consensus ad idem is required between all the conspirators for committing such a conspiracy. 

When any legal act is done through any illegal means, there has to be some overt act in pursuance of the agreement. Criminal Conspiracy is called an inchoate offence because it does not require commission of any action in addition to intention. 

The main essence of criminal conspiracy is what the parties have agreed to do and not the commission of the crime.

For example: A, B, C and D conspire to rob a museum of antiques for which they agree that A and B would threaten the manager and C would guard the door and D would keep a car ready for A, B and C when they successfully finish robbing the bank. Here there is a criminal conspiracy between A, B, C and D and therefore they shall be liable.