A high school student named Brett Bumpers (Weston) receives a mysterious package one day. It contains a bull penis totem with a note explaining that it will grant him three wishes. His first wish is for Samantha (Alexandra Holden) to go with him to a spring dance. The next day, Samantha invites him to the dance, and he suspects that his wish has come true. Samantha's boyfriend Cody is the star jock at the school, and he is humiliated by Samantha's decision.
In Australia in 1999, two British tourists, Liz Hunter (Cassandra Magrath) and Kristy Earl (Kestie Morassi), are backpacking across the country with Ben Mitchell (Nathan Phillips), an Australian friend from Sydney. Currently in Broome, Western Australia, they constantly get drunk at wild, extravagant pool parties and camp out on the beach. Ben buys a dilapidated Ford XD Falcon for their road journey from Broome to Cairns, Queensland via the Great Northern Highway.
In North Western Australia, highway patrol officers Gary Bulmer (Shane Connor) and trainee Brian O'Connor (Ben Gerrard) are parked by a rural road and are desperate to meet a quota for speeding tickets. Mick Taylor (John Jarratt), a pig hunter, drives past going under the speed limit and they pull him over, claiming he's going over the speed limit. After belittling and insulting Mick, the two officers give him a speeding ticket and an order to get rid of his truck. As they drive away, Mick uses his sniper rifle to splatter O'Connor's head, causing the cruiser to crash in a gully. Despite Bulmer's pleas, Mick breaks his leg and stabs him with a bowie knife, and places the fatally wounded officer back in the car before dousing it with petrol and setting it alight.
A couple is in their house having sex. One steps into the shower and comes out to find his girlfriend outside of the window lying dead with her throat slit, along with the words "you're next" written with her blood on the window. He himself is then killed by Lamb Mask by jamming his machete through his head.
On July 4, 1969, an unknown male attacks Darlene Ferrin and Mike Mageau with a handgun, at a lovers' lane in Vallejo, California. Mageau survives; Ferrin dies.
When a bloodied and incoherent Wu Zaijun (Wang Baoqiang) confesses to five murders that have not occurred, the police assume that he's mentally unstable and ignore his claims. Police detective Wong Wai-han (Sean Lau) is investigating a series of gruesome murders, but soon discovers that all is not as it seems and that not only are the murders connected, but that Jun is tied to them in some way.
During a period of time, two cases of murder occurred in the community. The victims include a young woman, whose corpse is said to have been frozen by the murderer using a special technique and being dressed up in a costume afterwards before being discarded like a mere doll. Police Captain Fang Youwei (Simon Yam) and his partner Yan Xiaotong (Ying Er), alongside newly recruited officer Xiao Kai (Yuan Hong) investigate this case. They find out that the two victims were college classmates ten years ago, and also stayed in the same Cosplay club. Fang approaches Zhou Jin (Vivian Hsu), who was classmates with the two victims. The appearance of Zhou lends the case a new direction and she seems to be the next target of the murderer.
One day, a man brings a luggage to the police report room. From the luggage, he takes out some files, a plastic wrapped scalpel and a half-filled vital out one by one and methodically placed it in front of the police while confessing that he killed a man and wants to surrender. He is actually involved in many murder cases during the past few months.
Veteran detective Tae-soo figures out that the suspect in a hit-and-run case, Gang-chun, is a serial killer wanted for several murders. But not long after his victory, Tae-soo realizes that his younger sister Soo-kyung was Gang-chun's last victim. Gang-chun receives the death penalty, but refuses to reveal the whereabouts of the victims' bodies, leaving Tae-soo and his brother-in-law Seung-hyun devastated. Three years later, Tae-soo is investigating the murder of a gangster boss when to his surprise, he finds evidence that Seung-hyun is the prime suspect. As he digs deeper, Tae-soo learns that the gang's former boss is now in the same prison as Gang-chun, who is thriving and looking better than ever (South Korea hasn't carried out a single execution since 1997).