The Crito is one of Plato's shorter dialogues, which deals with the days before Socrates's execution. Crito, one of Socrates's disciples comes to persuade him to escape from prison in view of his impending death. Crito is partially there to inform Socrates that he will be executed very soon.
Crito tells Socrates that he has procured a ship to get Socrates out. In addition, he tells Socrates that some foreigners have come to help him as well. In short, they will finance things. Finally, Crito states that Socrates has a moral responsibility to flee an unjust sentence of death. Moreover, he tries to persuade Socrates that he has obligation as a philosophical father to help his pupils.
Socrates will, of course, hear none of these things. He is filled with peace and calm even in the face of execution. More importantly, he says that it is never just to respond even to injustice with further injustice. Plato shows that Socrates is a philosopher par execllence, even in the face of death.