Here's the situation, I'm asking here since the the Shackled City board is mostly dead, and it's a rule question anyway.
I'm running this adventure path, and in a high level adventure, the adventurers must stop cultists to open a portal to a fiendish realm. They found a way to cast a wish spell and since they were too late and the portal was opened, they decided to wish for the portal to be closed definitively.
I thought that it's really above the guidelines of the spell, so I send the wisher into the future (and just him), when the portal has been finally closed by some epic adventurers. The player understood quickly he was sent in time, and want to try to come back. I told him it is going to be very difficult. He plans on tracking an NPC to have access to a wish spell, which is possible in the campaign.
But again, such a wish would be above the limits described in the spell. So it could be again dangerous.
What do you think ? Should it be possible ? Does a wish should be enough of more ? Another thing to do ? Another way for him to go back in time ? Ideas ?
Thanks in advance.