Has Star Trek: Picard just explained a far-future Q mystery from Star Trek: Discovery? While Jean-Luc Picard and his followers languish in the past, Captain Burnham's Discovery crew have ventured where no Star Trek series has gone before, roaring into the 32nd century, generations ahead of Gene Roddenberry's typical time frame. Needless to say, Star Trek: Discovery's far future looks drastically different. The Federation is shattered, nanotech is all the rage, and Vulcan has been renamed Ni'Var following a Romulan reunification.
Another major change is the Q Continuum's complete disappearance. Introduced in Star Trek: The Next Generation, the Q Continuum is a godlike species blessed with near-omnipotence and - until very recently - immortality. They've routinely meddled in galactic affairs, with John de Lancie's Q taking particular pleasure in tormenting Starfleet pal, Jean-Luc Picard. In Star Trek: Discovery season 4, however, Admiral Vance confirms no contact between the Federation and Q Continuum has been made for 600 years. Discovery is currently in the 32nd century, so applying some Vance math means the Q last popped up during the 2500s. For context, Star Trek: Picard season 2's present day is set in 2401.
Vance leaves Star Trek: Discovery a curious mystery - why did the Q Continuum suddenly stop appearing? Star Trek: Picard season 2 might provide an answer. No sooner had John de Lancie's Q made his return did Picard note how his old nemesis was different... somehow ailed. Immortal godlike beings don't typically suffer "under the weather" days and, sure enough, Q has struggled throughout Star Trek: Picard season 2, his finger-snapping magic oddly misfiring. In "Mercy," Q finally confirms to Guinan that he is facing death. Q is as surprised about this development as anyone, and isn't especially enamored with the idea of his existence coming to an end. Q doesn't appear to know the cause of his sudden mortality, but Guinan drops a potentially vital clue when she points out he can only be killed by his own species. By that logic, Q is either being targeted by another member of the Continuum (which he'd surely know about)... or every member of the Continuum is afflicted with the same ailment.
Star Trek: Picard hasn't yet revealed the specifics of Q's condition - the diagnosis, the cause, the cure, etc. However, Star Trek's Q Continuum are such a mysterious bunch, it's absolutely possible that the source of their power is somehow waning, and rather than an isolated case, Q's illness could represent the soon-to-be fate of his entire Continuum. Star Trek: Picard's Q-pocalypse was foreshadowed earlier in season 2, when Jean-Luc's mother referred to a wizard whose magic disappeared "in the very manner he had arrived by it." The wizard is a clear allegory for Q, and losing his magic points toward that becoming a problem for the broader Q Continuum - not just John de Lancie's mischief-maker.
According to Admiral Vance in Star Trek: Discovery, the Q don't disappear for another 100 years, but maybe this is simply how long a godlike species takes to die. Q could be the first of his people to fall ill, expiring at the end of Star Trek: Picard, before the remaining Continuum gradually ceases to continue until 2500 when none are left standing. That would certainly explain their mysterious vanishing in Star Trek: Discovery's future era, and it makes sense that Vance's Federation wouldn't know why the Q suddenly stopped poking and prodding them. Only a select few - the likes of Jean-Luc Picard and Guinan - are aware of Q's illness, and the other Continuum members probably wouldn't broadcast news their demise to the entire galaxy.
Star Trek: Picard continues Thursdays on Paramount+.