The destruction of the Earth which was witnessed by the crew of the Odyssey (as seen in the series 'Odyssey 5') took place in 2002. They were then thrown back in Time five years by an alien known only as "The Seeker", in order to stop this catastrophe from happening.
Apparently they were successful because Toobworld is still there! And still adding new "content" to the general population.
I'd like to think that not only did they succeed in their quest to save the planet, but they also got a little outside help - from The Doctor of 'Doctor Who'
Now, even though this is supposed to be David Tennant's victory lap before the series - with him as the star- ends and Matt Smith takes up the mantle in the next season, I'd rather have the Odyssey 5 take on "Leviathan" with a different Doctor....
The Eighth Incarnation, that is - as played by Paul McGann.
In theory, there could be thousands of TV characters who met the 8th Doctor through the years, but as we only got to meet him ourselves through that very muddled FOX TV movie in 1996, all of those other encounters would have to remain off-screen. And thus we could build up his collection of adventures without ever filming another sequence with McGann.
So that's what I'm proposing: the Eighth Doctor came to the assistance of the Odyssey 5 crew in defeating the plans of Leviathan to destroy the Earth.
Perhaps it was his encounter with Dr. Kurt Mendel which led to the regeneration of the 8th Doctor into the 9th incarnation. Something which stuck in his memory and influenced the supposedly random remix of his DNA. Because maybe I'm the only to see it, but there's something about the actor Sebastian Roche - especially as he looks now in 'Fringe' - that reminds me of Christopher Eccleston.... BCnU!