Vol 5 or 6, depending on who you ask, which is frustrating as a comic fan.
This was a cool hook: For reasons mentioned in secret, it’s time for Mr Fantastic to explore the unknown universe and meet all sorts of cool creatures and features, ultimately culminating in a weird confrontation with Dr Droom. That’s a big spoiler for the story, but it’s hard to not mention it with a cover like that.
The book had a neat hook: due to time dilation mcguffins, the Fantastic Four would leave earth, do their exploration, then be back in only a few minutes. Things being what they are though, the Fantastic Four knew that if they left for even a moment without a replacement team, something would happen that would force them to come back immediately, so they sign up four superheroes to be the “FF”. Not the Fantastic Four, that name is staying with the family, but just “FF”. There’s another series out there that’s included in a hardcover collection, but I didnt read that, I dislike the art in it and honestly I don’t have interest in the team that much.
This is a good series, right up until the last book, which is where the artist from the side series was brought over to close out the Fantastic Four series. I didn’t like the final issue and I’m sad that the original artist wasn’t able to finish the series.
A sidenote, this was the first book that I honestly tried to use the AR features that all the Marvel books had at the time, but the app is delisted and all the content is spread to the winds.
What a waste.