The Laches opens with a monologue by the character Lysimachus, speaking to two of his friends, Nicias and Laches. Lysimachus has just brought his two friends out onto a battlefield to watch a soldier fighting. Lysimachus explains that the reason he has brought his friends to the battlefield is that he and a friend of his, Melesias wish to seek their advice on how to best instruct their sons in the art of war. Lysimachus named his son Aristides after Lysimachus's own father and Melesias named his son Thucydides after his father. Lysimachus tells his friends that he is "resolved to take the greatest care of his youths, and not, like most fathers, to let them do as they please." He then gives several reasons why he believes his friends can help himself and Melesias.
Since the fathers of the two men were both great heroes in battle, Lysimachus and Melesias wish that their sons would live up to the honor of the name they hold. However, they are both worried that their children will have no example of greatness, since as Lysimachus says, "neither of us has any deeds of his own which he can show." Lysimachus explains that he is asking the advice of Nicias and Laches since they are themselves both great generals and must have an idea of honor and bravery. Furthermore, Nicias and Laches have already raised children of their own and therefore must have an idea of how to instill such virtues into a child. At the conclusion of Lysimachus's speech, Nicias replies that he and Laches would be glad to help their two friends in the instruction of their children.
Laches agrees with his friend Nicias that he wishes to help his friends' children but also recommends that Lysimachus consult Socrates. Laches states that Socrates is "always passing his time in places where the youth have any noble study or pursuit." Nicias seconds Laches's recommendation, stating that Socrates recently supplied Nicias's own son with a music teacher of inestimable value. At this point, Lysimachus himself realizes that the Socrates whom the other men speak of is also the son of Sophroniscus, a great friend of Lysimachus and has also been spoken about often by his son. Laches then states that Socrates is not only a famed teacher of youth but is himself a shining example of a courageous warrior. Laches goes as far as to say that if other Athenians had acted as courageously as Socrates had acted during the battle of Delium, in which both Socrates and Laches fought together, then the city would have won the war.
Upon hearing this, Lysimachus asks Socrates if he would please join Laches and Nicias in the instruction of his and Melesias's children. He asks first if Socrates believes that the art of fighting in armor is a practice in which children may be advantageously instructed. To this question Socrates replies that he wishes to be of as much use as possible to the two men. However, Socrates states that he is too young to speak knowledgably about this matter and must consult his elders—the two older generals.
In the opening section of the Laches there is not an overwhelming amount of actual philosophy taking place. In this dialogue as well as in many others, Plato allows other characters to set the stage with their own remarks before Socrates begins to complicate the picture. That being said, there are several important pieces of information gestured at by Plato in these opening lines.
The fact that Lysimachus asks two distinguished generals for advice rather than two teachers of the art of fighting is itself noteworthy. There is a subtle but consistent thread in Plato's early philosophy that in order for a person to be a successful teacher of an art, that person must be a shining example of the success of that art himself. Socrates is also a notable example of a person whose knowledge of courage derives from his own personal experience. The fact that Socrates fought valiantly in the battle of Delium may seem like a small detail of the dialogue. By the end of the dialogue, however, it becomes increasingly relevant as we are led to see that perhaps the only way of having knowledge of courage is by practicing it. It is also worth noting that Socrates is known by Laches and Nicias as a man who passes his time teaching young people. It is this widespread reputation as a consort of youth that lead to his conviction and his death as it is told in Plato's dialogue The Apology. In The Apology, however, Socrates is considered by his accusers to be a corruptor of youth rather than a teacher of knowledge.