A Delightfully Convoluted Mess
Big Finish's very first Doctor Who audio drama features the Fifth, Sixth, and Seventh Doctors teaming up to save Gallifrey, because apparently one Doctor isn't enough to fix the universe's problems—you need three versions of the same Time Lord having a mid-regeneration crisis management meeting.
Gallifrey is facing destruction from an overwhelming enemy, and naturally, each Doctor gets individually manipulated into mucking with time in three separate storylines that are totally-not-confusing-at-all.
The Seventh Doctor, ever the knight in shining velvet, rescues a mysterious young woman on a distant planet and decides to prevent the death of a crippled old war criminal—because why wouldn't you save a war criminal? It's not like that could have any temporal consequences.
Meanwhile, the Fifth Doctor finds himself on a German WWI submarine and prevents the vessel from sinking, presumably while looking adorably confused in his cricket outfit and wondering how he ended up in a tin can underwater instead of playing cricket at Lords.
Not to be outdone in the "terrible life choices" department, the Sixth Doctor insults a young woman at a tourist resort—which, let's be honest, is the most in-character thing he could possibly do—and then tries to sort out whatever mess is happening there, probably while wearing his traumatic coat of many colors.
Here's the kicker: it turns out the Doctors accidentally changed time for the worse, and these time anomalies will feed malevolent Clock Roaches called "The Sirens of Time." Oh, and that young woman who kept popping up? Always the same person, named Lyena, who engineered this whole elaborate scheme. Because of course she did. Nothing says "efficient villain" like appearing three separate times to trick three separate versions of the same person.
If the Doctors obey the Sirens' call more than once, they'll be forever trapped in their thrall, but Lyena threatens to kill the Fifth Doctor if they disobey—holding the cricket-loving incarnation hostage, which is just rude. A creature called the Temperon offers the Doctors a deal: free it, and it'll go back in time and destroy the Sirens at the beginning of time, because time travel paradoxes are apparently best solved with MORE time travel paradoxes.
So there you have it: Big Finish's inaugural story where three Doctors learn that the real enemy was the time-tampering they made along the way. The ending ties everything up but feels rushed, probably because someone realized they had to wrap up three different storylines and a cosmic threat in under thirty minutes. It's ambitious, it's messy, and it's exactly the kind of gloriously complicated nonsense that Doctor Who does best.