Batman Begins

As a child, Bruce Wayne falls down a dry well and is attacked by a swarm of bats, subsequently developing a phobia of the creatures. While watching an opera with his parents, Thomas and Martha, Bruce becomes frightened by performers masquerading as bats and asks to leave. Outside, mugger Joe Chill murders Bruce's parents in front of him. Orphaned, Bruce is raised by the family butler, Alfred Pennyworth.
Fourteen years later, Chill is freed in exchange for testifying against Gotham City mafia boss Carmine Falcone. Bruce intends to murder Chill, but one of Falcone's assassins does so first. Bruce's childhood friend, assistant district attorney Rachel Dawes, berates him for attempting to undermine the justice system, saying that his father would be ashamed. Bruce confronts Falcone, who tells him that real power comes from being feared. Bruce decides to travel the world and learn how to confront injustice. In Bhutan, he meets Henri Ducard, who trains him as a member of the League of Shadows, led by Ra's al Ghul. After completing his training and purging his fears, Bruce learns that the League intends to destroy Gotham, believing it to be corrupt and beyond saving. Bruce rejects the League's cause and burns down their temple during his escape. Ra's is killed by falling debris, while Bruce saves the unconscious Ducard.
Bruce returns to Gotham intent on fighting crime. Inspired by his childhood fear, he takes up the vigilante identity of "the Batman" and sets up a base in the caves beneath Wayne Manor. He takes an interest in his family's company, Wayne Enterprises, now run by the unscrupulous William Earle. Company archivist Lucius Fox allows Bruce access to prototype defense technologies including a protective bodysuit and a heavily armored car called the Tumbler. Bruce poses as a shallow playboy to allay suspicion.
Batman intercepts a drug shipment, provides Rachel with evidence against Falcone, and enlists Sergeant James Gordon, one of the few honest cops left in Gotham, to arrest him. In prison, Falcone meets with Dr. Jonathan Crane, a corrupt psychiatrist who he has helped smuggle drugs into Gotham, and threatens to reveal his complicity if he does not declare him mentally unfit for trial. Crane puts on a scarecrow mask and sprays Falcone with a fear-inducing hallucinogen that drives him insane, and has him transferred to Arkham Asylum. While investigating "the Scarecrow", Batman is exposed to the hallucinogen and left incapacitated. He is saved by Alfred and given an antidote developed by Fox. When Rachel accuses Crane of corruption, Crane reveals that he has been pouring his fear-inducing drug into Gotham's water supply. He doses Rachel with it, but Batman saves her and subdues Crane, who claims to work for Ra's al Ghul. Batman evades the police to get Rachel to safety, administers the antidote, and gives her a vial of it for Gordon and another for mass production. Ducard reappears at Bruce's birthday party and reveals himself to be the actual Ra's al Ghul. Having stolen a powerful microwave emitter from Wayne Enterprises, he plans to vaporize Gotham's water supply, rendering Crane's drug airborne and causing mass hysteria that will destroy the city. He sets Wayne Manor on fire and leaves Bruce for dead, but Alfred rescues him.
Ra's loads the microwave emitter onto Gotham's monorail system, releasing the drug as the train travels toward the city's central water source. Batman rescues Rachel from a drugged mob and indirectly reveals his identity to her. He pursues Ra's onto the monorail and fights him just as Gordon uses the Tumbler's cannons to destroy a section of the track. Batman refuses to kill Ra's, but also chooses not to save him, gliding from the train and leaving Ra's aboard as it crashes and explodes.
Bruce gains Rachel's respect but loses her love, as she decides she cannot be with him while he is Batman. Bruce buys a controlling stake in the now publicly traded Wayne Enterprises, fires Earle, and replaces him with Fox. Gordon is promoted to Lieutenant of the Gotham City Police Department, shows Batman the Bat-Signal, and mentions a criminal who leaves Joker playing cards at crime scenes. Batman promises to investigate, and disappears into the night.

Question: What does Bruce intend to fight when he returns to Gotham?
Answer: Crime; Crime