There is a witch coven in the warehouse of a tattooist called Hai Lee (Burt Kwouk). One of the witches nicknamed Momma Rose (Alibe Parsons) thinks that she has seen something else this time.
Frank Rowlett (Dirk Benedict) is a selfish man, in love with himself, as the picture in a frame of himself comes to prove. He owes money to some thugs, but can't repay them. He thinks he doesn't have enough money to repay his debt at the time, but he's about to get married to millionaire woman, who is usually very generous to everybody. He counts to marry Sara Helston (Jenny Seagrove), because she's already accepted his proposal. However, the thugs are already making an exception of Frankie's case by allowing him to live twenty four hours more, but they are not going to wait for two months or more until that wedding happens, and one of the thugs even tells Frankie to consider that delayed deadline as an engagement present.
Matt Helston (John Paul) is Sara's father. She insists that she's going to marry him, and doesn't to want to listen to Matt's concerns about Frank's lack of supporting means. Meanwhile, Frank goes to play poker at a seedy warehouse in a seedy street. Frank tries to exchange his watch and his car for money to play, but the lady who calls the shots there will only accept cash tonight. So Frankie has to go to a pawn shot to cash onto some goods, and ends up at Hai Lee's. He doesn't even notice a prostitute, (Dinah May). He interrupts Hai in the middle of making a tattoo.
Hai admits that it's an expensive watch and has to go to get enough money to pawn it. Frankie is left waiting outside of Hai's private office, thinking about it all. He will miss the watch for sure. Through the ajar door, he notices the place where Hai Lee hides all his money. The woman who was having her tattoo done, Cara (Hillary Crane), decides to leave it for some other day. Frankie pretends to have left the shop, and sees Hai accompanying her to the door. He enters Hai's private office through a corridor where there is the hanging voodoo doll of a demon and steals all his money. Hai admires Frankie's old luxurious watch and then enters his office already knowing that he's being robbed. In the ensuing fight, he is killed. Frankie notices a small rash in his chest, dismisses it and gets all the money he can rob. Dusting off everything he's touched, waits for the whore and her client to go, and then leaves.
When he arrives to the poker house, he realises that he's left his watch at Hai Lee's parlour, as Ma Perkins (Maggie Rennie) takes for granted that pawning it was the way to get the money and mentions it. However, he keeps on playing, and he wins it all. Frankie wakes up, exhausted, when Sara phones him to tell him that they have his father's consent to marry. In Frankie's shirt, there is a blood stain which passes unnoticed.
Det. Inspector Grant (George Sewell) and another police officer, Det. Sergeant Kirby (Peter Settelen) immediately notice the luxury watch. Frankie repays the thugs and meets Mr Helston officially. The three of them lunch and swim in their private swimming-pool. Sara realises the new spot. He says that he must have burnt himself when having a shower. We see a huge black mole in the middle of his chest. He puts on a plaster on top of it. They three decide to have a little wedding next Saturday.
The police interrogate the tattooed girl. The thugs are very surprised about Frankie having got the money all of a sudden. Sara and Frank give their fun engagement party. The prostitute tries to hit on Kirby, but he doesn't even notice her. They are about to make love, but Frankie notices that the mole has grown bigger than the plaster, so he dresses up and leaves
He sees Dr. Melford (Reginald Marsh), who has never seen anything like it. The hand-sized mole is the tattoo about the murder Frank has committed. Melford calls the police about it, but Frank batters him.
Frank goes to another tattooist to try to erase it off, but the tattooist feels terrified and won't do it. Frank tries to hide it by burning it off with an iron. He wakes up when Sara calls him, and he saw that it was useless: the tattoo grew bigger. Sara notices that he's strange, not feeling well, and doesn't want to meet with her.
That night, Frank dreams of the idol heads, the masks at the tattoo parlour and how Hai Lee attacked him with a knife and left a mark on his skin.
It's the 24th, his wedding day. Westcott (Tom Adams), his best man, wakes him up. Father Dowd (James Ellis) is performing the votes. When he picks up the ring, he realises that the tattoo has spread to his arms. Frank says "I do" anyway. There is a moment of strangeness, everybody has noticed the moment of hesitation.
During the reception, Frank runs to the toilet. Sara is convinced that something is going wrong. He reassures her. Kirby and Grant arrive to question Frank about the watch, which he alleges was stolen on Wednesday. He doesn't admit to have ever met Hai Lee. The police has not other option than leaving.
In their wedding night, Frank is afraid to get naked. The police are still suspecting him. In spite of everything, Frank is able to make love to Sara, albeit with all the lights off. After that, they go to sleep, and Frank's got a terrible nightmare, dreaming about the moment when Hai Lee created that first small spot on his skin during their fight. Sara realises that he's having a bad dream, turns on the light and can see the huge tattoo on Frank's body for the first time. The tattoo is a fixed accusation, showing the moment when Frank killed Hai Lee. Frank brutally slaps Sara.
Carla has identified Frank because of a picture of the wedding on the social section of the local newspaper. The thugs have been following Frank all the time. Thinking that it would take years to come back to their single apartment, they are looking for the money robbed from Hai Lee's. Frank's tattoo distracts the thug, and Frank has the chance of stabbing him. The other thug tries to reason with him to no avail.
Frank doesn't know what else to do. Finally, he confesses to Father Dowd. He tries to tell him that money won't be of any help, so Frank leaves, covered with a scarf and a hat, as the tattoo has grown even to his face.
Grant and Kirby find the two dead thugs in Frank's apartment. Sara is distraught, feeling lonely. Frank offers all the money he's got to Chong Woy (Robert Lee), to do magic for him and get rid of the tattoo. Rose doesn't know whether she's strong enough to counterbalance such powerful magic.
Frank comes back to Hai Lee's parlour. The voodoo dolls and masks are still all over the place. He feels desperate, and gets naked - but for a slip. He sees Hai's ghost. Hai Lee jumps out from the mirror and strangles him. This time, Hai Lee wins.
In her room, Sara wakes up alone. Looking out from the window, she sees a dead bird on the sidewalk.
At Hai Lee's, Frank is dead, while Hai Lee's ghost blurs away. Frank's skin is completely white and pale, without any tattoo.
--written by KrystelClaire