The climax in Nothing But the Truth occurs as both Miss Narwin and Philip are faced with the choice of returning to school. Miss Narwin is asked to take a leave, or "sabbatical" as Dr. Doane would put it. She sees past the euphemism to understand that they are really asking her to resign. Philip, on the other hand, after being teased by the other students who claim to be gathering an 'anti-Philip, pro-Narwin' petition, tells his parents that he will not return to Harrison High School.
Both of these instances act as the turning point or climax, because if Philip or Miss Narwin had insisted on returning to Harrison High School, then the conflict could have continued on indefinitely. Instead, neither chooses to return, and the falling action and resolution shows Miss Narwin hopelessly resigning her beloved English job and Philip ironically finding himself at a new school with no track team.