In this chapter, Tris Prior embarks on her initiation into Dauntless, a faction symbolizing bravery and courage. The initiation process is rigorous and demanding, designed not only to test physical strength but also mental fortitude and emotional resilience. Tris quickly realizes that she is competing against other initiates who are just as determined, if not more so, to prove their worth and claim a spot in this fierce faction.

As the training begins, Tris is introduced to her instructor, Four (Tobias Eaton), who is known for his strict but fair approach to teaching. Four’s presence has a significant impact on Tris, as she finds him both intimidating and intriguing. The initiates are subjected to a series of physical tests, including combat training, where they learn the importance of strategy, strength, and agility. Tris struggles initially, feeling out of place in a world that values fearlessness, especially coming from a background in Abnegation where selflessness was paramount.

Throughout the training, Tris is forced to confront her own fears. Each initiate has their own strengths and weaknesses, and the competition quickly escalates. Tris's determination drives her to push through her limitations, but she also grapples with her identity as a Divergent—a fact she must keep hidden, as being Divergent could lead to dire consequences.

The chapter also highlights the dynamics amongst the initiates. Rivalries and alliances begin to form, and Tris quickly realizes that the friendships she hoped to cultivate might be harder to maintain than she anticipated. The social hierarchy within the initiates becomes apparent, as those who were born into Dauntless seem to have an advantage over newcomers like Tris. This reality brings both internal and external challenges for her as she navigates her new life.

Moreover, the physical training is interspersed with moments of personal reflection for Tris, as she contemplates her decision to leave Abnegation and embrace a life of bravery. The chapter illustrates her internal conflict between her previous life and the expectations of her new faction.

Overall, 'Training Begins' sets the stage for the intense competition and psychological challenges that lie ahead for Tris. It captures her evolution from a hesitant recruit into a fierce contender, while also emphasizing the themes of identity, fear, and the struggle for acceptance in a world that measures worth by one’s ability to face danger head-on.