Ten years later Snow White (Lily Collins) has just turned eighteen and while Queen Clementianna does not care for her, the palace staff loves her, especially the baker Margaret (Mare Winningham). Margaret tells Snow White that the kingdom is rightfully hers and that she should go outside and see what has become of her people. Snow White then defies the Queen's orders and leaves the palace, intent on seeing the conditions of her kingdom. In the forest, she meets Prince Andrew Alcott (Armie Hammer) and his companion Charles Renbock (Robert Emms) who have been robbed by thieving dwarfs. She and the Prince are drawn to each other but go their separate ways. Snow White arrives in the town the palace overlooks, and discovers it is barren and the once-happy people are destitute due to Queen Clementianna's greed. Angered that the Queen has destroyed everything her father worked for, Snow White decides to overthrow her stepmother.
Prince Alcott finds his way to the palace. Queen Clementianna, realizing he comes from a wealthy kingdom, throws a ball to woo the Prince and get him to marry her so she can solve her financial problems. Snow White secretly attends the ball planning to ask the prince, whom she believes she has not met, to help her restore the kingdom. She and Alcott learn the truth about each other when they are partnered in a dance. However Queen Clementianna notices them dancing and seizes Snow White, who finally stands up to her stepmother, telling her she has no right to rule as she does. Seeing Snow White as the threat she always feared she would be, Queen Clementianna orders her manservant Brighton (Nathan Lane) to take the princess into the forest and feed her to the Beast that lives there. Brighton takes Snow White to the forest, but is unable to kill her. He releases her and tells her to run. Snow White flees the Beast (Frank Welker) and collapses at the door to the Seven Dwarfs' house.
Queen Clementianna goes to her Magic Mirror, a portal to a bleak and barren world that contains a house full of mirrors. Within the mirrors lives Queen Clementianna's reflection (Lisa Roberts Gillan) who is much wiser, kinder, and somewhat younger than her. The Queen requests a love potion so she can make the Prince fall in love with her. The Mirror Queen repeatedly warns Queen Clementianna that there is a price for using dark magic, but she refuses to listen. Back in the forest, Snow White wakes up to find herself surrounded by the dwarfs Grimm (Danny Woodburn), Butcher (Martin Klebba), Wolf (Sebastian Saraceno), Napoleon (Jordan Prentice), Half Pint (Mark Povinelli), Grub (Joe Gnoffo), and Chuck (Ronald Lee Clark). After much debate, they agree to let her stay with them for one night.
Queen Clementianna levies another tax against the people to pay for the parties she throws for Prince Alcott even though the town magistrate says that the people cannot tolerate much more. Brighton collects the taxes, but on the way back to the palace, the dwarfs rob Brighton and steal the money. When Snow White finds out that the Dwarfs are thieves and that the stolen money belongs to the townspeople, she is angry. The Dwarfs explain that no one stood up for them years earlier when the Queen expelled them from the kingdom because she thought they were ugly. Snow White sneaks away while they are distracted to return the money. The townspeople and the Town Magistrate (Alex Ivanovici) are overjoyed to have their money back and Snow White lets the Dwarfs take credit for it, earning them the people's acceptance and gratitude. The Dwarfs agree that Snow White can stay permanently if she agrees to become a thief like them. She agrees, but only if they can steal from Queen Clementianna and give back to the people.
Meanwhile, Queen Clementianna informs Alcott that Snow White is dead and attempts to get him to marry her only to be interrupted by Brighton. When the Prince finds out that the bandits have robbed Brighton, he goes after them unaware of the awful things the Queen has done. In the forest, Alcott discovers that Snow White is not only alive, but in league with the bandits. Each believing the other to be in the wrong, Snow White and Alcott duel. Alcott returns to the Palace defeated and informs the Queen that Snow White is alive and in league with the bandits that stole her money.
Queen Clementianna consults her Magic Mirror again and demands that the Mirror Queen punish Brighton for lying to her. The Mirror Queen turns Brighton into a cockroach and Clementianna tells the Mirror Queen to use its magic to kill Snow White. Despite the Mirror's warning about using dark magic, she agrees to accept whatever consequences her actions may bring. It is revealed that the Queen used a love potion to make Snow White's father fall in love with her. However the potion she uses on the Prince turns out to be a 'puppy love' potion and the Prince becomes utterly devoted to her. She uses the Prince's new found devotion to get him to agree to marry her. When Snow White learns of the wedding, she is heartbroken. Queen Clementianna then uses dark magic to create two giant wooden puppets in the forest and uses them to try and kill Snow White and the Dwarfs. Snow White is able to cut the strings of the puppets and break the mirror's spell, but she decides to run away to protect her new friends. The next morning, the Dwarfs find her gone and discover a note she left them telling them that she loves them all. They intercept her just as she is preparing to leave and convinces her that their lives are better with her.
The royal wedding is put into preparations as the spell that was placed on Brighton wears off. They decide to crash the royal wedding, and do so, robbing the noble guests of their clothes and valuables. Queen Clementianna arrives at her wedding in the middle of the chaos and discover the Prince has been captured by Snow White upon learning this from the noble guests. Queen Clementianna tells Brighton that "if you want Snow White killed, you have to do it yourself" as she leaves. Back in the forest, the Prince (still under the spell) wishes to be with the Queen. The Dwarfs and Snow White come to the conclusion that they have to use true love's kiss, which will break any spell. Snow White kisses Alcott and the spell is broken.
Queen Clementianna arrives in the forest intent on killing Snow White herself. She reveals that she can control the Beast that has been plaguing the forest and sends it after Snow White. Snow White fights the Beast with help from the Dwarves and the Prince, but all are soon overcome. As the Beast is about to deliver the killing blow, it hesitates and Snow White sees that it wears a necklace with a moon charm on it similar to the one the Queen wears. She cuts the chain with her father's dagger and the Beast suddenly becomes engulfed in light. In the Mirror House, Queen Clementianna is gloating, but suddenly realizes something is wrong. She begins to age and the Mirror Queen Clementianna tells her that this is her consequence for using dark magic. The Beast turns out to be Snow White's father who has no memory of the last ten years. Grateful to Alcott for his assistance, he agrees to let him marry Snow White.
The King has Snow White and Prince Alcott engaged in front of the entire kingdom. During the wedding celebration, a crone in a hooded robe appears and offers Snow White an apple (which is the poisoned apple) as a wedding gift. Learning that the crone is what has become of Clementianna, Snow White cuts a piece of the apple, offers it to Clementianna, and remarks it is time to accept that she has been beaten (something the Queen once said to her). Accepting defeat, Clementianna takes the apple as the Mirror Queen declared that it was Snow White's story all along. The Mirror House is subsequently destroyed along with the mirror portal to it.
The film's epilogue reveals what happened to the Dwarfs: Grimm writes a book of fairy tales, Napoleon becomes a hairdresser, Wolf rejoins his pack, Half-Pint finds a girlfriend, Grub just eats, Butcher becomes a flyweight champion, and Chuck joins the royal circus.