5 Days A Stranger is the first game in the Chzo Mythos series, developed by Ben Croshaw using Adventure Game Studio and released on September 22, 2003 on the Fully Ramblomatic homepage. It centers on the supernatural events surrounding the gentleman thief Trilby and four others who struggle for their lives against an unknown force as they try to escape from their imprisonment in DeFoe Manor.
The player takes control of the famous cat burglar known only as Trilby, using a point-and-click interface to interact with the environment and other characters. The story is told over the course of five seperate days spent within Defoe Manor. Each day is separated from the next by a dream sequence which require no player interaction.
Trilby, a self-described gentleman cat burglar, comes to DeFoe Manor at the request of an associate after the last heirs have died off and the valuables are up for grabs. Upon entering the manor, Trilby finds himself stuck in the house by some supernatural force along with four other people: Phillip Harty, a self proclaimed "treasure hunter", Simone Taylor, a correspondent for the BBC who came to the manor to film a documentary, Jim Fowler, a high school student who entered the manor on a dare, and a mysterious man known only as AJ. After gathering all but AJ, the four decide to try to find a way to escape the manor the next morning. That night, Trilby has a dream where he awakes to find everyone dead, killed by a masked, hulking figure carrying a machete. The figure lifts his mask to reveal Trilby's face.
Into Day 2, Trilby awakes to find Phil hunting in the backyard for a secret tomb, and Simone in the newly found library. AJ is still nowhere to be found. Upon inspecting a map to convince Phil that the secret tomb is not within reach, Trilby gets a vague suspicion that there's something on the map he hasn't seen, despite his full search of the house the day before. After convincing Phil to stop looking for the tomb, Trilby finds AJ dead, tied to the bottom of the swimming pool in the back yard. After discussing this with his three remaining companions, Phil blames Trilby in a fit of rage.
Into Day 3, Trilby breaks into more rooms to find the diaries of Sir Roderick and Matthew DeFoe, the original owner and his son, respectively. Matthew's diary refers to a boy "behind the door in the kitchen" that his father seems to ignore. On Matthew's fifteenth birthday, the last entry, it reads: "My father has done a terrible thing. All this time he pretended there was no boy behind the door, and now this. There is blood all over the kitchen floor. I will do what I can. Then we can be a family together and be happy." In Roderick's diary, it tells of his wife's death in childbirth, and the last entry (also Matthew's fifteenth birthday), reads: "It is the anniversary of the night I unleashed a horror. A horror which I tonight shall remove from this world. May God forgive me." Having previously found an article explaining that Roderick and Matthew had mysteriously disappeared on Matthew's fifteenth birthday, Trilby becomes suspicious.
Using a white magic spell to find Matthew's body, Trilby locates a secret dungeon behind a wall in the kitchen. Manacles hang from one wall, and after digging under some of the dirt, Trilby finds Matthew's and Roderick's bodies. At this moment, a loud crashing noise sounds from the opposite side of the house. When Trilby goes to investigate, he finds a broken glass jar that had previously encased a wooden idol, and the idol lying on the floor. When Trilby touches it, he is immediately knocked unconscious. Trilby then wakes up wearing a welding mask and holding a machete, lying next to Phil's corpse. When he sits up, he looks around briefly before being knocked unconscious again, this time by Simone.
When Trilby awakens, he is locked inside a shed without his tie that holds the emergency lock pick or any other items. The shed is being guarded by Simone, who tells him that he killed Phil. She says the tie was removed after Jim said Trilby might hang himself with it. After failing to convince Simone to help in all other ways, he manages to convince her that suicide might not be so bad for him. She then slips him his tie, which he then uses to pick the lock on the shed with. Once he exits the shed, he finds Simone gone. After searching the house, he finds Simone upstairs, who has now caught up with the fact that Trilby was possessed when he killed Phil. The masked figure from Trilby's dream then enters and tries to kill Trilby and Simone. Trilby quickly knocks the figure out by tripping it with the rug it stands on. After the mask is lifted, the figure now turns out to be Jim.
After putting Jim to bed, Trilby and Simone deduce the story behind their predicament: though Matthew was reported as Roderick's only child, Roderick actually had twins, the first being Matthew and the second being the cause of his wife's death. Overcome with grief and believing the second son to be a demon, Roderick chained that son up in the basement, causing mental retardation and insanity. After Roderick beat that son half to death on his fifteenth birthday using the African Idol, the son adorned a welding mask and leather apron, and killed Roderick and Matthew with a machete before dying of his own wounds. His soul was sealed in the wooden idol he was killed with. Since then, he possessed anyone who touched the idol and killed anyone they found, thinking it was his father coming to torture him again. Trilby would later name the second son John out of convenience.
Trilby locates John DeFoe's skeletal remains in the upstairs bathroom, which are shown to be deformed, heavily suggesting that John DeFoe was born physically deformed and that was partially why his father so strongly hated him. With a black magic spell, Trilby summons John's soul into John's corpse. Simone and Jim, positioned around the body, are then possessed by the spirits of Roderick and Matthew respectively, and unwittingly reenact their last conversation prior to their deaths. Simone shoots the body with a rifle. It then falls into the fireplace that spreads fire everywhere. The entire manor burns, and the group finally escapes. Trilby lets Simone and Jim think he died in the fire to avoid the police, who had surrounded the front of the building prior to it burning down. Now free, Trilby remarks that his first order of business is to give the associate who originally sent him to DeFoe Manor a punch to the face.
Yahtzee -upon failing to research his own game- made the mistake of a retcon in the series, in 5DAS, John, Roderick and Matthews deaths occur on June 28th, in all other games, the "Day of the King" is July 28th.