In this kind of fanfiction, Robin might be in a lot of danger. Slade could be using Robin to get to Batman. He might try to brainwash Robin and turn him against his friends. For example, he could lock Robin in a secret lair and show him false information about Batman to make Robin question his loyalty.
Well, in a fanfiction where YJ Robin is kidnapped by Slade, one possibility is that the other members of the Young Justice team would immediately start a rescue mission. They would use their unique skills and powers to track down Slade's hideout. For example, Aqualad might use his connection to the water and sea life to gather intel, while Superboy could use his strength to break through any barriers in their way. Robin himself would likely be using his wits to try and outsmart Slade from within the captivity.
It's also possible that Nightwing and Slade end up having a long conversation during the captivity. Slade might try to convince Nightwing to join his side, perhaps by appealing to some sense of justice that he thinks Nightwing is missing. Nightwing, of course, would resist, but this could lead to some interesting character development for both of them as they debate their different ideologies.
The other Teen Titans could also play a big role in the rescue. Starfire could use her powers to fly in and distract Slade while Cyborg and Beast Boy create a diversion. Raven could use her magic to break any spells or traps that Slade has set for Robin. They would all work together as a team to get Robin back safely.
Robin would probably stay calm and observant. He's been trained well, so he'd immediately start looking for any weaknesses in his captivity situation. He might try to pick the locks on his restraints if he's bound, or find a way to communicate with his team secretly if there's a chance.
One possibility is that Robin, being kidnapped, will have to rely on his own wits and skills he has learned from Batman. He might try to outsmart the Joker by finding weak points in the place where he is held captive. For example, if it's an old warehouse, he could look for ways to escape through the ventilation system or by using some tools he might find around. And the Joker, being the unpredictable villain, could be constantly taunting Robin, trying to break his spirit before Batman arrives.
Batman, of course. He's Robin's mentor and protector. He has the skills, the resources, and the determination to track down Slade and rescue Robin.
The plot might go like this. Slade kidnaps Robin in a very stealthy way. He takes Robin to an abandoned building. There, he tries to indoctrinate Robin into his way of thinking. He could be telling Robin that Batman is using him and that he can offer Robin more power. However, Robin stays true to his beliefs. Meanwhile, Batman is on a frantic search for Robin, following every lead, and the Bat - family is also on high alert. Robin is constantly looking for an opportunity to turn the tables on Slade and escape.
Well, Batman could start a massive search for Robin. He'd use all his detective skills and his gadgets to track down Poison Ivy. Maybe he'd enlist the help of other heroes too, like Nightwing. And when he finally finds where Robin is being held, there'd be an epic battle between Batman and Poison Ivy.
Well, one possibility is that the other members of Young Justice immediately start a search and rescue mission. They might use their unique skills and powers to track Robin down. For example, Superboy could use his super strength to break through any barriers in their way, while Miss Martian could use her telepathy to try and sense Robin's location. Another scenario could be that Robin manages to escape on his own using his wits and combat skills. He's been trained well by Batman, so he might be able to outsmart his captors.
Well, in such a fanfiction, perhaps they could be kidnapped by a super - villain who wants to use their powers for evil. The story might then focus on their attempts to escape and the challenges they face while being held captive.