In which there is a great Shattering of mirrors, and our Heroes arrive in Mirage, a city near to the Spire.
Just putting up some random ideas I've had about the first episode.
Mirror Portal: Minor role-playing encounter. May occur in Mirrage or pretty much anywhere else.
The PCs help unpack and set up a Mirage mirror portal. They have an opportunity to talk to the folks who delivered it and direct its setup. Topics might include how the mirror functions and where it was made. The PCs are likely to get a totally inaccurate story attributing the portals' creation to dopleganger craftsmen in Mirrage. That they may have studied ancient artifacts to do so will not be mentioned unless the PCs are perceptive enough to realize the workers are being less than forthcoming. That the mirror is itself one of these artifacts will not come up. Mention of the kamerel is right out.
The PCs might also be treated to some stogy old codger's opinion of the new portals:
Look, berk, those new mirror portals tain't natural! Don't trust 'em! Why, I heard tell of an adventurer who went missin four, five days after stepin' into one of those infernal contraptions. When (s)he finally came out the other end, why, white as a Cainian snowstorm (s)he was. Made straight for the nearest portal off the Outlands, too. Raises goats on some stupid little Prime, I hear.
Of course, the Mirage workers are quick to defend their product and to belittle the old man.
After setup is complete, the PCs have an opportunity to step through the portal as a test. If one or more do so, the DM shouldn't do anything bad, although one PC might catch a glimpse of a mysterious white-haired humanoid (a kamerel) while in transit.
Mirror Malfunction: minor role-playing encounter, however it sets up a major combat encounter later in the campaign. Should probably occur during transit to Mirrage, after the Shattering has occurred.
This event begins when the party all travel through a mirror portal together. While in transit, they experience feelings of discomfort and have the distinct sensation of pushing forward against great resistance. However, they arrive safely on the other end, none the worse for wear. In deed, their is nothing to suggest that anything unusual happend at all. However, about a day after they travel through the portal, their Mirror dopplegangers emerge back at the PCs departure point. As normal, the dopplegangers are Alignment-flipped versions of the PCs with all the PCs memories up until the point the mirroring occurred. The dopplegangers are aware of their status and begin to plot against the PCs.
Palace Intro/Arcanum Blackmantle: Major combat event. Most definitely occurs in Mirrage, after the Shattering.
Arcanum Blackmantle convinces the PCs to seal off the inner areas of the Palace of Broken Glass. This is easier than it seems, because, oddly enough, the Palace seems to be designed with such an action in mind. Arcanum can't do this himself, as he knows a little something about what's running around in there. Of most pressing concern are Mirror Elementals that can duplicate any power or spell cast in their presence, which makes them almost as dangerous to him as they would be to a group of low-level rubes. So he may as well get the rubes to take care of it.
Athar snack run: minor roll-playing encounter. May occur as the PCs begin to get on the Athar's good graces.
A rather straightforward task: travel to tradegate, buy some grain, bring it back. An opportunity to fight some random encounters, see some scenery, and chat up some Athar namers.