I want to imprison my characters for a long period of time, but I don't want them to use any spell or skill to escape before their imprisonment and I certainly don't want to kill them in the process by having to many guards or something. There are six 5th-level PCs: bard, paladin, monk, ranger and sorcerer. I want to add some kind of totalitarian regime that will imprison them for at least 20 years, without me having to roleplay the 20 years along. have in mind that time travel is not an option since I want the players to feel some sort of hate towards this regime.
in a creative and fun way, how can I get them imprisoned without having them fighting back?