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The main conflict in The Fault In Our Stars concerns Hazel Lancaster's inner struggle to come to terms with her terminal form of cancer and the possibility of dying young.  To this end, she attends Cancer Support Group, which she secretly loathes but continues to visit because it makes her parents feel better about how she is coping with her illness.  When she meets Augustus Waters at one of the meetings, his positive and unique outlook influences her perspective on her situation.  Ultimately, when Augustus dies, Hazel is left alone at the end of the novel, but realizes that although she can not control her circumstances, she can make her own decisions and choices. 

What is the climax in The Fault in Our Stars?

The climactic event in a novel, such as The Fault in Our Stars" , is the pivotal moment when "something" happens and a lot of consequences happen as a result of it. Aside from being the moment of highest intensity in the reading, it is also the agent that will produce the most changes in the original sequence of the reading, sometimes even moving the plot away from its original path. The result of the climactic event is the denouement, or the falling action. This is often easiest to identify and, for this reason, I recommend that you always look at the part of a literature work where things begin to turn towards a final point. The catalyst that caused those events to take place is the climax.

In The Fault in Our Stars the characters of Augustus and Hazel, two young terminal cancer patients, meet in their support group, demonstrate a clear attraction to each other, and even begin to share common interests, such as the books by Peter Van Houten, who is a writer whom they both admire. Augustus builds the rising action that leads to the climax when he starts exchanging letters with the writer, which is a bold move on Augustus's part and something that means a lot to Hazel. That alone is a change of the usual events in the novel that surely will lead to something big.

And it does! The climax starts to develop in the form of "The Genies" foundation sponsoring Augustus dream to fly to Amsterdam and visit the alcoholic and reclusive author that he and Hazel admire so much. This big event start the sequence of events (all quite pivotal) that entirely turn the story to another direction.

• First, Peter Van Houten, although generous, was rude and mean to the kids because he had no idea that the entire visit was a trick by his representative to try and get him to stop drinking. The situation was bad enough for Augustus to even yell at Van Houten.
• Shortly after, Augustus and Hazel kiss at Anne Frank's house, declaring their feelings for each other.
• In that same visit, Augustus also makes his ultimate confession: that his cancer had metastasized and that he did not have...