During May Sweeps, we'll be seeing an 'NCIS: LA' crossover with 'Hawaii Five-O' on CBS.
NCIS agents G. Callen and Sam Hanna will show up in Honolulu on the first night, which I guess will be on their usual night of Tuesday. And then the following Monday (I'm assuming), Steve McGarrett and Danny Williams will be heading over to the mainland to interact with the others on the NCIS team in Los Angeles.
And for all I've blathered on about this version of 'Hawaii Five-O' being in a parallel dimension, you know what? This isn't going to be a Zonk.
That's because for those two nights, we'll be watching the LA-based NCIS team from that parallel dimension. This storyline will not be involving the characters from the main Toobworld version of the show.
Those familiar with the concept of the Toobworld Dynamic already know that this 'Hawaii Five-O' reboot lost its chance to be part of Earth Prime-Time when they forego being a continuation (like 'Star Trek: The Next Generation') and chose instead to go the reboot route (like 'Battlestar Galactica'.)
So if 'Hawaii Five-O' is going to cross over with 'NCIS: LA', then for those two episodes we'll be seeing alt-Callen and Company from the TV dimension of the new 'Hawaii Five-O'.
'NCIS: LA' doesn't have a clean slate in the main Toobworld, however. It's a spin-off from 'NCIS', which in itself was a spin-off from 'JAG'. And on 'JAG', Dean Stockwell made a few appearances as the Secretary of the Navy, Edward Sheffield. (No relation to Maxwell Sheffield, I imagine....)
And THEN! Sheffield crossed over to a short-lived series about the Supreme Court - 'First Monday' starring James Garner. But by that point, Sheffield left the Administration's Cabinet and had been elected (re-elected?) as a Senator. (Hopefully the state was never revealed. That always works out better for Toobworld.)
Now, the Secretary of the Navy, no matter what universe, may think he's got an important job, but in Toobworld it doesn't really matter. Not many shows are going to bring in that character or even mention him, so it could be anybody in Toobworld. The same can't be said for the President, of course. Plenty of shows will make a reference to the current occupant of the Oval Office. So whoever is the current POTUS in the real world MUST be the same person in Earth Prime-Time.
So it is with the Supreme Court, even though I don't think most Americans can even name every member of the Bench... and full disclosure, I'd probably have to strain the brain to do so. A change now and again could be splained away, but the Justices were totally swept out for 'First Monday'. (The same thing happened with 'The Court' and 'Outlaw', but that's a whole different kettle of fish for other TV dimensions.)
And yet the real Team Supreme have shown up or, at the very least been mentioned, on several TV shows - among them, 'Boston Legal', 'Picket Fences', and the TV movie "Recount".
At least in this case dealing with 'First Monday', we can rely on the TV essential of the 'Primeval' reboot of the Toobworld timeline to put right what once went wrong. That temporal adjustment happened at the end of season one for 'Primeval' (March, 2007, based on its original airdate in the UK.) Since 'First Monday' was broadcast in 2002, its characters and events would have been swept up and out in the tele-revision. The characters of Thomas Brankin, Henry Hoskins, and Joseph Novelli, along with the other six Supreme Court justices and their staffs all still exist in Toobworld somewhere, but at best they are Circuit Court Judges; none of them are currently sitting on the Supreme Court bench in Earth Prime-Time.
Edward Sheffield probably survived the seismic change in the timeline as well, and may yet be a Senator since the real ones can be replaced so long as the home states of the televersions are never mentioned. (This is one of the two main reasons why 'Brothers & Sisters' had to be relocated out of the main Toobworld. The female governor of California during the years of the Governator was the other reason.)
So that temporal reboot is what keeps 'JAG', 'NCIS', and 'NCIS: LA' in the main Toobworld. But it doesn't help the new 'Hawaii Five-O' at all. No televisiologist in his right mind (which I admit is an oxymoron) would ever toss out twelve seasons of the original 'Hawaii Five-O' to accept this upstart into the main TV Universe.
And therefore this upcoming crossover will have no effect on whatever happens in Earth Prime-Time.
As the original Steve McGarrett once said, "Aloha, Suckers."