Theseus, the King of Athens' son was upset the citizens of Athens had to be sacrificed and decided to go kill the Minotaur.
Theseus joined the other people of Athens going to Athens to be killed. He promised his father if he returned alive he would put up the white sail rather than the black sail.
Princess Ariadne. King Minos' daughter fell in love with Theseus and decided she didn't want him to die. She handed him a ball of string in which he should attach it to the entrance and unroll it as he headed inwards so he could follow his path out again. She then said he had to marry him when he survived. He promised he would then he entered the labyrinth.
Theseus held the string and unwound it as he lead the others into the darkest depths of the labyrinth towards the Minotaur.
Theseus found the Minotaur asleep at the heart of the Labyrinth. With the Minotaur half asleep, Theseus battled him to victory. Theseus then exited the labyrinth, following the path of string.
Theseus sails home with all the people from Crete and Ariadne.