A year later after a mysterious attack outside the apartment complex, the masked killer responsible targets the residents of that building who are complicit to the murder victim.
One year ago, guests arrive at a party during the summer solstice period to celebrate. At night, one of the partygoers Kit Jennings wanders alone at the street after the party on his way back to the Clayborne apartment building when he encounters a person wearing a hooded costume and a neon-lit mask standing near the local coffee shop. Kit, drunk and dazed, turns to the masked person and mockingly laughs before making his way back to his apartment. However, unaware to him, the figure follows him from behind as Kit turns to the figure who pulls out a knife and rushes to brutally stab him two times in his gut. Shocked and panicked, Kit began screaming for help to the other tenants while he's bleeding and limps inside to the apartment's back stairwell. The killer reaches to the door as Kit failed attempting to prevent it from following him as he was chased through the hallways. He pleads for Cassidy Olenski, one of the residents who had come home from the party, to let him in to her apartment but she angrily rebuffs him for his recent hookup with the other partygoers until she saw Kit's stab wounds and the killer following him before closing the door in fear. He managed to reach to his apartment but his key was missing at the door until the killer reaches and stabs him repeatedly in the back. Kit runs to a drunken Dan who refuses to help him and saw the killer chases after him who reached the main entrance as Dan steps back in shock. Kit runs back outside the building through the lot until he was knocked out on the road by a yellow car. The driver Amy Chao was shocked by this and tends him who was still breathing until the other tenants rushed outside and panicked at the chaos, including Cassidy, the Dixon family, local high school teacher Kaili Greenberg, the immigrant Jalalzai family, the Rijkers family and foster mom Amber Ciotti, Violet Lickers and husband Joe Lickers, gay activist Angel Lopez and barista Xander Lemmon. Kit mumbles in pain before dying from his injuries as Amy screams in distress.
The following year after the incident, the residing tenants do their respective daily activities before starting the day: Ms. Greenberg texted interactual messages with her date Kyle, Frank Dixon was watching a viral video in the bathroom until he was told by his wife Kate that their daughter Erica must use the shower to prep for school, Angel preps breakfast and checks on his tablet to read the news on racial issues, Amy was sleeping while Xander who was her boyfriend dresses for work and Violet records her current vlog at her personal website "Sex and Violets". Saadia Jalalzai wakes up at 6am to get dressed for the final day of the school exams before summer break while her parents Azlan and Farishta packed their things to return to Afghanistan for the graduation of her brother Ferhan. Her parents are worried for her staying alone at their apartment but she assured that she'll be fine despite the killer who murdered Kit have not been caught. As she began to leave, her father gave a smartphone to her as a gift in order for her to text them regularly just in case. Before heading to school, Saadia passed Dan who was attempting to enter his apartment until she decided to help him. At the Rijkers apartment, the siblings Connor and Jen had to deal with Amber who had suffered one of her mental episodes after the previous incident as Jen, who didn't got any sleep before preparing for the exams, left while her brother watches Amber.
Back at their apartment, Frank verbally abuses Kate and threatens her but stopped after Erica arrives to leave for the exams before she could see the action until Frank left. At the street, Frank stole his car back and parks while he argues with a person on his phone intending to conceal his car theft. After speaking, he saw Kit's attacker from earlier standing there but ignores as he turns back to check the car's scratch, the killer rushes to him behind and brutally swings his axe to Frank's neck. He turns to the killer shocked and bleeding profusely as the killer deliver three more vicious swings that hacks his neck before finishing with a final blow, decapitating his head as it rolls onto the road. Back at the apartment building, Ms. Greenberg, who was still texting with Kyle, overhears her resident next door Cassidy having sex with a man and began masturbating on the wall.
At Cassidy's apartment, she had to go for her final exams for her senior year before heading to college. The man whom she had flungged was shocked at Cassidy's actions and began to leave the building in disgust. Dan, who had posted his racist message at a white liberal website, saw the commotion and was disgusted at his daughter's promiscuity that resulted in a heated argument between father and daughter until Dan confiscates Cassidy's phone and destroys it by stomping on the ground as she storms off to her room in anger. At the cafe, Saadia bought lattes from Xander who talks classy into advertising his other products to her as Jen arrives and intimidates his products. She then tried to invite Saadia at the summer solstice party at night after their final exams. The girls and Xander saw a passing police car outside as the police investigate Frank's death. The detectives Roberta Hanson and Pujit Singh found his head placed at the hood of the car while his corpse was at the front seat. Singh showed his driver's license to Hanson who recognizes Frank as she had interrogated him of Kit's murder by the killer known as "The Druid" but turns to the public who are snapping the crime scene and lashes at them for their actions of sharing this online. The posts of Frank's death spread across social media, including news sites, and at the cafe despite Cassidy's protests, Erica checks on her phone and was horrified of her father's death.
At the school; Saadia was confronted by Cassidy who verbally assaulted her, accusing her of publicizing the scene. Cassidy continues to inflict more violence on the young Muslim student, eventually pulling off her hijab, but Ms. Greenberg arrives to stop the fight and sent Cassidy and her friends to the principal's office while escorting Saadia to a classroom. At the Dixon's residence, Hanson interrogates on Frank's background before the previous incident at the building to Kate and Erica, who are both mourning for his death. From a flashback at the aftermath of Kit's death, Frank was interrogated by Hanson and revealed that after having gotten home and saw Kit limping out of the main entrance while being chased by the Druid, he saw the killer and attempts to cock his gun to stop the attack but the Druid points his knife and threatened him before leaving as Frank, who was scared, decides to go against helping Kit until his death.
Back to the present at the classroom, Ms. Greenberg comforts Saadia who decided to continue the exams despite the teacher's suggestion to reschedule after the bullying incident. She appreciates her self-independence before giving her advice to not let people like Cassidy bring her down in life before leaving as the students including Jen arrive to take the Algebra exam. While taking her exam, Saadia suffered PTSD after remembering the past incident when she attempted to help Kit while he was attacked by the Druid but she was restrained by her father before she might get involved. Her math teacher snaps her out of it to check on her before Saadia decided to walk out to refresh herself but when she began to give her phone to the teacher, she realized it was missing. At her apartment, Violet pulls a prank on Joe that Amber was pouring herself with a gasoline tank filled with water mimicking a self-immolation as Violet laughs in amusement after recording but Joe scolds her for that humiliation and convinced her to delete the video when she attempted to post it on her website. He was consoled by Angel who was his affair. After recording her second take of the video, Violet records her vlog to update her insights during the one-year anniversary of the building's first attack including Frank's death, implying that the Druid is back. Back at the school, Saadia attempts to look for her phone while she is being watched by the Druid.
Meanwhile, Cassidy was revealed to have stolen her phone in order to video chat a hook up with another man at the girl's washroom. As she prepares to go back to her classroom, she noticed someone was inside when hearing a sound of liquid pouring. Thinking it was student who embarrassed itself, she playfully taunted the person before leaving but the door was lock, leaving her trapped inside. As she began screaming for help, the person with her inside is revealed to be the Druid and grabs Cassidy, dragging her screaming to one of the toilets. The Druid grabs her head to submerge it in there, revealing to be contained with acid which burns her jewelry. She screams for help, attempting to fight back but the killer dunks her head to the acid that burns her face before repeatedly submerging her there until her face completely corrodes and the Druid drops her dead before walking away.
|Victim||Cause of Death||Background|
|Kit Jennings||Stabbed repeatedly and accidentally hit by Amy's car||Killed in a crime of passion due to Kit's connection to the other tenants.|
|Frank Dixon||Decapitated in broad daylight||After getting home late and saw the Druid attack Kit a year ago, he is supposed to report Detective Hanson on incident. He armed himself in the gun to deter the attack but the killer threatens him before leaving as he decided to do nothing otherwise.|
|Cassidy Olenski||Head drowned in hydochloric acid||Due to their earlier strained conversation, she refused to let Kit in her apartment until the killer chases after him in the hallway.|