How to end a scenario with no end

[Last Hussar]

More help needed for RPG scenario!

So, as I said I am running a scenario. I was struggling to come up with one, when I found an absolutely bonkers one-shot on line. This is the intro;

THE HALLS OF THE MAD MAGE
The archmage Callisto once claimed to have "conquered the insight of the seventeen quasi-dimensions of the elder lords of Oud". It was not long before he had become  known as the Mad Mage. But perhaps there was some method in that madness: His long-abandoned sanctuary – inhabited now by his former slaves and arcane experiments – is a place where space is contorted impossibly upon itself.

Halls of the Mad Mage

So the original idea was just somewhere for the party to explore. I took this as the heart of the scenario, and wrote an expanded "We're a bit worried about him, go and find out what's happened" story.*

The problem is, it doesn't have an actual end; originally its just a light hearted dungeon romp.  I've made minor changes to the 'Mobius room' with the pictures, and that's about it.

The fact is, Callisto isn't there to be found - I'm happy about that, I have a hook I can use in further scenarios if I want.

The problem is - How the hell do I get the players to realise they aren't going to find him in this scenario? The Möbius pictures now lead to very much deadends (eg a bottom of a well), or places they have no chance of finding him if he did go there 10 years ago (a desert, a city).

*I have used Tollin from the Guards of Traitors Toll as the place they are initially sent, just to mess with them.

[Ithoriel]

The party enter a large hall, musty and dank, it has clearly been empty for a long time. There are no obvious doors except the one they entered by.

At the far end a pair of candles flicker into life, they are clearly attached to the wall. Something shiny is below them.

A voice says,"Ooh! People! Eugh! Not quite our sort! Oh my! Where are my manners? It has been so long .... WELCOME!"

If the party engage it in conversation it will declare itself to be The Magic Mirror of the Mad Mage.

If asked the whereabouts of Callisto/ The Mad Mage it will reply with the following

Over sea, under stone
Hanks of hair, shards of bone
Eldrich shackles hold him fast
Bony fingers bonds have cast
Everliving, Ever dead
Bind the thoughts within his head
The Blade of Shadows you must find
If you seek to free his mind!
The Blade's location? Is in a tome.
Now, if you ask, I'll send you home.

Somewhere in the world there is a stone fortress set upon an arch of the same stone joining a tower of rock with the mainland. Turbulent waters swirl beneath. Guarded by undead and ruled by an ancient LIch who wields the Staff of Unliving, the fortress is bleak and forbidding. Callisto believes the staff makes the wielder immortal but actually it turns them into a lich. Callisto's attempt to use his ability to bend space to steal the staff has not gone well.

The Staff of Unliving makes the lich almost unkillable, however damage taken will eventually render the lich immobile and unable to use magic. Only when in that state can the Blade of Shadows be used to kill the lich and destroy both the Blade and the Staff. Not to mention blasting everyone and everything about it with magical energy.

How Callisto feels about the Staff's destruction I leave up to the GM.

The location of the Blade of Shadows is currently unknown.   

[kustenjaeger]

Have a diary/lab book with entries up until around the time he left/disappeard for the party to easily find?

Edward