Why are Will and his two companions making their way to the Games in the opening of the novel, The City of Gold and Lead?

Will Parker and his two companions make their way to the Games, the sports competition held every year to pick humans who will become slaves in the Tripod cities. Will and his companions hope to enter the city, learn about the Tripods, and return to the White Mountain with the information needed to end the Tripods' control over Earth.