It's Spidey and Doctor Strange vs. Doctor Doom and Dormammu in one epic Annual!
At the start of this annual, a page from the Book of the Vishanti can be seen. It says that once every sixty thousand years, the Bend Sinister is going to be possible, and that it shall cause gravest harm to humanity unless a sorcerer and one who "is equally spider and man" join together to stop it. In Castle Doom, a short man named Dilby has just succeeded in harness and combine the powers of both magic and science, allowing the possibility of the Bend Sinister to occur. Doctor Doom is then summoned, who orders for Dilby to test the device which he has succeeded in creating, and Dilby is transported to the Dark Dimension of Dormammu. Dilby is then taken to Dormammu, who soon communicates to Doctor Doom that Dilby has arrived as they have planned. Dormammu then says that he has given Dilby some magic powers, but unknown to Dilby, he may not survive the use to which he will be put.
In Greenwich Village, Doctor Strange is studying a book when he suddenly feels a sense of danger nearby. He heads down the stairs to find a large box which has been delivered to him, although he didn't order such a thing. He opens the box to find what seems to be a large mummy, but upon Doctor Strange using the Eye of Agamotto on it, the mummy’s bandages break apart and it turns out to be a large robot, which immediately attacks Doctor Strange. Upon realising that his mystic bolts are having no effect on the robot, Doctor Strange tries using the Crimson Bands of Cytorrak to bind it, but the robot simply walks through them. The robot then manages to repel another of Doctor Strange's attacks from it, and so Doctor Strange realises that the only thing he can do is to escape in his astral form. However, on the astral plane there are hundreds of small demons trying to break into Doctor Strange's Sanctum Sanctorum. Their sheer number is too much for Doctor Strange, who does the only thing he can; sending out a psychic flare to anyone who might be able to help him.
After passing the headquarters of several superhumans, the flare goes to Peter Parker, who gets a vision of Doctor Strange asking for help. Unfortunately, Peter is teaching class at the moment, but one of his students accidentally starts a fire with chemicals, giving Peter a chance to flee the building and go to Doctor Strange's Sanctum, dressed as Spider-Man. Upon reaching the Sanctum, Spider-Man is attacked by two gargoyles, which come to life when he approaches. Although they're made of solid rock and hard to damage, Spider-Man manages to coat one in webbing, then spin it around and throw it at the other, shattering both gargoyles into pebbles. Spider-Man then heads to the ground to keep looking for Doctor Strange, but is attacked by some imp-like creatures which rise out of the footpath and start attacked him. No matter what Spider-Man does, he can't shake then off, and so he leaps into the roof of Doctor Strange's Sanctum, where he's safe from the imps.
Spider-Man then enters Doctor Strange's Sanctum, where he finds Wong. Wong tells Spider-Man that Doctor Strange has been abducted, and that before he was taken, he managed to send Wong a telepathic message consisting of four letters- C.B.G.B. The only place Spider-Man knows of with that name is a nightclub, and so he heads there, although he knows that it's an unlikely place to store a hostage. When he gets there, he changes to his civilian clothes as a disguise to get in. In another place in the club, Doctor Strange is being held by Dilby, Doctor Doom's assistant from the start of the annual. Dilby then asks Doctor Strange if he's scared about the Bend Sinister, and then says that it won't matter- as the Bend Sinister requires a human sacrifice, who in this case will be Doctor Strange.
Inside the club, Peter Parker is looking for Doctor Strange, still not quite sure if it's the right place where Doctor Strange has been taken. Peter then sees someone who seems to recognise him from high school, but whilst he's trying to shake her off, Debbie Whitman coincidentally arrives and thinks that Peter is cheating on her, as they were going to go to this very club before the whole business with Doctor Strange occurred. Whilst Peter goes after Debbie to try and explain, Debbie runs into Dilby, but neither she nor Peter recognise him as the man planning the Bend Sinister. Peter and Debbie keep going to a coffee shop, where Peter promises to explain what happened. When they're there, the band from the nightclub passes, all chanting "Bend Sinister". Peter realises that something's wrong, and so leaves Debbie to change back to Spider-Man.
Spider-Man notices that whoever the band pass, they too join them in marching and chanting "Bend Sinister", until there are hundreds of people doing it. Spider-Man wants to help them, but he suspects that if he gets closer he'll join in the chanting, and so simply has to watch. The crowd head to the Latverian Embassy, where Dilby is standing on the roof with Doctor Strange strapped to a massive gem called the Eldritch Crystal. When the moon shines through the gem and onto the crowd, the Bend Sinister will be complete, although Dilby is planning on using its power all for himself, rather than for Dormammu and Doctor Strange. Spider-Man then arrives to stop Dilby, who summons the robot which he used to defeat Doctor Strange. As it chases Spider-Man around, he too is unable to stop it, whilst Dilby muses that there are only a few more seconds until the Bend Sinister is activated.
Spider-Man manages to use his webbing to block the robot's eyes, which starts flying out of control. Spider-Man manages to work out how to control it, and flies the robot towards Dilby, shattering the crystal which holds Doctor Strange. Doctor Strange then tries to stop Dilby, saying that he's been thinking up of spells to stop Dilby whilst he was in captivity. However, as Doctor Strange casts the spells, a barrier forms around Dilby, and a portal opens. Through the portal a hand appears, which drags Dilby into the portal. Meanwhile, the people have recovered, and Doctor Strange thanks Spider-Man for his help. Asking if he can repay Spider-Man in any way, Spider-Man asks what the Bend Sinister is. Doctor Strange refuses to say, saying that it's better that mankind doesn't know, before flying off.
Back in Latveria, a package arrives for Doctor Doom. Inside is a miniaturised Dilby imprisoned inside a crystal, his punishment for trying to steal the power of the Bend Sinister all for himself. Doctor Doom then says that he will make an amusing addition to his collection, and goes to the top of his castle, where he says that although the experiment is finished, he is not, and has more plans....