Arrival in New York and the Errant Niffler
Newt Scamander, a British Magizoologist, arrives in New York City in 1926. He carries a magically expanded briefcase full of various magical creatures. He intends a brief stopover on his way to Arizona, but his plans quickly go awry. While watching Mary Lou Barebone, a No-Maj (American term for Muggle) who leads the anti-witchcraft group 'The New Salem Philanthropic Society,' a mischievous Niffler escapes from his case. Newt tries to recapture the Niffler, chasing it into a bank vault. There, he accidentally swaps his case with Jacob Kowalski, a No-Maj baker hoping to get a loan for his own bakery. This swap starts a series of events involving Newt and Jacob.
The Introduction of Tina Goldstein and the MACUSA
While Newt chases the Niffler, Tina Goldstein, a demoted Auror from the Magical Congress of the United States of America (MACUSA), sees him. Tina, witnessing the magical chaos, mistakenly thinks Newt intentionally exposed the magical world to No-Majs. This is a serious violation of American wizarding law, which unlike the British system, enforces strict secrecy. She arrests Newt and takes him to MACUSA headquarters, hoping to get her old job back. However, her superiors, President Seraphina Picquery and Director Percival Graves, dismiss her concerns. They are focused on a more dangerous, destructive magical force terrorizing the city.
Jacob's Encounter with Magic and the Erumpent
Jacob Kowalski, having accidentally swapped cases with Newt, returns to his apartment. Curious about the strange latches, he opens Newt's magically expanded briefcase, accidentally releasing some of Newt's creatures. One of them is an Erumpent, a large, rhino-like beast that is dangerous when in heat. The Erumpent escapes into the city, causing major damage and attracting Newt and Tina, who must now work together. Newt, understanding the seriousness of the situation, enlists Jacob's reluctant help to recapture his creatures. He promises to remove Jacob's memories once the task is complete, as No-Majs cannot remember the wizarding world.
The Goldstein Sisters and the Obscurus Investigation
Newt and Jacob go to Tina's apartment, where they meet her sister, Queenie Goldstein, who is a Legilimens. Queenie, charming and empathetic, quickly understands Jacob's situation and likes him. While Newt and Jacob try to round up the escaped creatures, the sisters become more involved. They learn about the growing threat of an Obscurus, a dark force that appears in magically suppressed children. Director Graves, meanwhile, secretly investigates the Obscurus. He believes it is connected to the Barebone family, especially Credence, Mary Lou Barebone's adopted son, whom he manipulates with promises of magical training.
The Execution and Escape
Because of the increasing magical incidents and fear of exposure, MACUSA arrests Newt and Tina. They are held responsible for the chaos and sentenced to death: Newt for illegal creature possession and endangering the Statute of Secrecy, and Tina for harboring him. They are taken to the MACUSA execution chamber, where they are to be submerged in a memory-wiping potion. However, with Jacob and Queenie's timely help, who create a diversion and use their combined magical and No-Maj cleverness, Newt and Tina escape from MACUSA headquarters. They are determined to clear their names and find the true source of the city's magical destruction.
Credence's Struggle and Graves's Manipulation
Credence Barebone, a timid and abused young man, is constantly persecuted by his adoptive mother, Mary Lou, for any hint of magic. Director Graves, pretending to help Credence discover his magical abilities, exploits his vulnerability. He promises to teach him magic if Credence helps locate the Obscurus. Graves believes the Obscurus is manifesting in one of Mary Lou's other adopted children. However, as the film goes on, it becomes clear that Credence himself is the Obscurial. He has suppressed his immense magical power for years due to trauma and abuse. His suppressed magic is about to erupt with catastrophic consequences for New York City.
The Revelation of the Obscurial
Credence Barebone is tragically revealed to be the Obscurial. His years of abuse and suppression of his magical abilities cause the Obscurus to burst forth in a devastating display of uncontrolled power. The Obscurus manifests as a dark, swirling cloud of destructive energy, tearing through the city and causing widespread devastation. This exposes the magical world to the No-Maj population. This event confirms Newt's earlier suspicions about the dark force and its danger. MACUSA, Newt, Tina, Jacob, and Queenie are all drawn into the escalating crisis, realizing the true scale of the threat.
Confronting the Obscurus and Graves
The rampaging Obscurus, controlled by the distraught Credence, causes immense destruction across New York. Newt, Tina, Jacob, and Queenie, along with MACUSA Aurors, try to contain the creature and calm Credence. During this intense confrontation, Director Percival Graves arrives and reveals his true intentions. He tries to protect Credence, not out of compassion, but because he wants to use the Obscurus's power for his own evil plans. Graves openly defies MACUSA, further showing his sinister agenda and confirming his connection to the dark events plaguing the city. This leads to a direct magical confrontation with the combined forces of MACUSA and the protagonists.
Grindelwald's Unmasking
In a confrontation, Newt, with help from MACUSA Aurors, overpowers Graves. Newt uses a unique magical creature, a Swooping Evil, to subdue Graves and reveal his true identity. In a shocking revelation, Graves is unmasked as Gellert Grindelwald, one of the most dangerous dark wizards of all time, who had been operating in disguise within MACUSA. Grindelwald's exposure clarifies his manipulation of Credence and his plans to start a war between the magical and No-Maj worlds. His capture is a significant victory for the wizarding community, though it hints at a larger conflict to come.
The Memory Charm and Farewell
To prevent widespread exposure of the magical world after the Obscurus's destruction and Grindelwald's unmasking, Newt releases his Thunderbird, Frank. Frank disperses a rain-like magical substance over New York City that acts as a mass memory charm, erasing the recent memories of the No-Maj population regarding the magical events. Jacob Kowalski, as a No-Maj, must also have his memories erased, a poignant moment for Newt, Tina, and Queenie, who have grown fond of him. Newt gives Jacob a silver Occamy egg as a parting gift, subtly influencing his future. Newt then says goodbye to Tina, promising to deliver his book in person.
Jacob's New Beginning
After his memories are erased, Jacob Kowalski returns to his ordinary life, seemingly unaffected by his adventure. However, the silver Occamy egg Newt gave him is made of pure silver. Jacob uses the proceeds from selling the egg to get the loan he needed. He successfully opens his own bakery, specializing in pastries shaped like Newt's fantastic beasts, a subconscious echo of his forgotten magical experiences. Tina and Queenie visit his bakery, and while Jacob doesn't consciously remember them, there's a flicker of recognition, hinting at the lasting, if unremembered, impact of his time with the magical world.