Quite hard to follow as it's several years since I've read any Fantastic Four but entertaining nonetheless. There are three simultaneous tales involving all four members of the FF, one involving Namor, one involving Galactus and the Silver Surfer and one involving the Negative Zone. There are quite a few characters that I do not recognise but that generally does not spoil anything.
Well-illustrated, this is worth a look especially if you're a recent reader: it'll mean more to you than it did to me. Spoiler alert: there are tragic events at the end.