A Vigilante follows the life and work of Sadie, a woman that has survived domestic abuse and now wishes to serve her own form of justice throughout the world. Sadie reinvents herself as a ruthless vigilante who is solely concerned with correcting the injustices in the world. Despite not having much money, she manages to survive and relies on small donations from the people whose lives she saves.
The first mission that we see of Sadie is her visit to the house of a husband that is abusing his wife as well as his child, under the pretense of selling medical insurance. Instead, she beats up the man and forces him to transfer all of the money from his bank account to the account of his wife and to never go near them again. She saves the life of the woman and her child, with her only request being to ask her to put anyone else that needs help in contact with her.
As the film carries on, we flashback and forth between the past and present, where we gain access to the experiences of Sadie and then see how it affects her in the present day. We see her attending a group therapy session that is intended for domestic abuse survivors, and after a while, we are finally told Sadie's own story. We come to learn that she escaped from her abusive husband with her young son, but that she managed to chase them out while being armed with a knife; hurting her son.
