Ignatius Perrish, played by Daniel Radcliffe, is an outsider in his town, but none of that affects him as he is deeply in love with Merrin Williams, portrayed by Juno Temple. Their romantic moments, shared under a tree with sweet kisses, seem idyllic. Merrin playfully asks if he’s feeling "horny," to which Ig sheepishly responds that he is "getting there." He promises to love her forever, but in turn, all she asks is for him to love her for the rest of her life.
However, tragedy strikes when Ig wakes up on his floor, clutching a bottle of vodka, only to discover the horrifying news that Merrin has been murdered. Outside, protesters gather with signs eloquently condemning him. Ignoring the chaos around him, Ig desperately calls his lawyer friend, Lee Torneau, hoping for assistance. He retreats to his family's home to evade the press, but the support he seeks from his brother Terry, played by Joe Anderson, and his father Derrick, portrayed by James Remar, only reveals their mixed feelings. Derrick, rather than expressing unconditional support, seeks a lawyer out of obligation—many are pushing Ig towards a plea deal despite his protests of innocence. Lee then delivers devastating news: the evidence that could clear Ig’s name was destroyed in a forensics lab fire, leaving him with no way to prove his innocence. Incensed, Ig pledges to hunt down Merrin’s true killer.
His quest for justice leads him to a bar, where the fearful bartender refuses to serve him due to the murmurings surrounding his guilt. Yet, Glenna, his old friend played by Kelli Garner, takes pity on him and offers him a drink, a gesture Ig initially declines in his desire for solitude. When the townspeople gather for a vigil by the tree where Merrin's body was discovered, her distraught father Dale, played by David Morse, voices accusations against Ig. Seething with anger and pain, Ig reacts defiantly, desecrating a statue of the Virgin Mary, fueling a growing resentment towards God for his perceived indifference to Merrin’s suffering.
The next morning yields a bizarre twist; Ig awakens to find horns sprouting from his head. He shares this with Glenna, who laughs it off, showcasing her complex relationship with their tragic circumstances. A bizarre series of encounters continues at the doctor’s office, where Ig is subjected to the twisted thoughts of the people around him, exposing their innermost desires and fears. He sees disturbing visions as people project their issues onto him, suggesting a wicked alteration in how people perceive him since the horns began growing.
In emerging memories, we glimpse Ig’s childhood and his initial admiration for Merrin, linking to pivotal moments in their relationship, including a profound incident with a cherry bomb that forged a bond of guilt and connection. As events unfold, Ig’s frustrations mount; he suspects his friend Lee may have a deeper connection to Merrin and her tragic fate. After tracing events back to a diner where he planned to propose, he learns of a interplay of love, greed, and jealousy that guided each of their actions on fateful nights.
When the truth begins to unfold, revealing the real killer, Ig’s frustration turns into a driving force for vengeance. Denouncing the lies perpetuated by a waitress named Veronica, played by Heather Graham, who plays a significant role in distorting his image, Ig struggles against the tide of chaos surrounding his accusation. With new revelations, including treachery that runs deep among those he once trusted, Ig’s resolve encapsulates the torment of losing Merrin, and he becomes a living embodiment of wrath and sorrow.
As a confrontation with Lee unveils the horrifying reality of what transpired that fateful night in the woods—a violent rage ignited over misunderstandings and jealousy—Ig realizes the depth of betrayal. With each interaction, no one seems to grasp the full horror of the situation until Ig finally comes face to face with the truth. Amidst darkness, a final showdown leads Ig to transcend into otherworldly justice, incinerating the sins of those who wronged him and Merrin.
In the aftermath, miraculously emerging from the lake, he returns to tackle unresolved issues and embrace the memory of his lost love. A key phrases to reunite with cherished memories ultimately steers him toward closure, restoring both his connection to Merrin and delivering a harrowing yet poetic chapter on loss, love, and the haunting echoes of the past. The film poignantly concludes with a heartfelt scene encapsulating Ig and Merrin under the tree once more, suggesting their destined reunion lies beyond the depths of despair.
