Short answer:
Nothing happens.
Explanation:
First and foremost, the restriction for agents and Wizardhavens only applies to movement, not to the site where an agent is revealed. According to the MEWH rules:
And according to the CRF, Rulings by Term, agents:A tapped or untapped agent may move to a non-Haven, non-Under-deeps site in the same region or in an adjacent region (see below). The agent taps if not already tapped.
Finally, in order to check the legality of the agent’s movement when it is revealed, the only sites that matter are the ones that the agent moved to. From MEDM:Agents may not move to any version of a hero Haven, unless they have a special ability allowing them to.
Only Elven agents can move to a site that is a Wizardhaven.
To summarize, the restrictions on moving to Havens and Wizardhavens are only checked at the time that an agent is revealed, and are only checked in regards to sites that it moved to. An agent that doesn’t have a series of sites through which it has moved can therefore legally be revealed at its home site that is currently a Wizardhaven in play.If one of your agents is revealed before it has moved, you must immediately choose which home site it is at-place the appropriate site card with the agent. If you do not have such a site card in your location deck, discard the agent at the end of the current turn.
If one of your agents is revealed after it has moved, the first site card that was played must be one of its home sites or it must be in the same region as one of the agent’s home sites or it must be in a region adjacent to a region that contains one of the agent’s home sites. Any site card other than the first site card must be in the same region as the previous site placed on the agent or it must be in a region adjacent to the region that contains the previous site placed on the agent.
If one of your agent’s series of sites indicating its travel is illegal, the agent has no effect. In addition, it is immediately discarded and any site cards associated with the agent are returned to your location deck.
Here are some practical examples:
Example A:
Turn 1. I play Juoma face-down; he is considered to be at any of his homesites.
Turn 2. I move my face-down Juoma to Weathertop (which is currently a regular Ruins & Lairs).
Turn 3. I move my face-down Juoma to Old Forest.
Turn 4. During his organization phase, my opponent plays Hidden Haven on Weathertop, turning the site into a WizardHaven.
Turn 5. My opponent enters Old Forest. I reveal Juoma, and now we have to check his movement. Since Weathertop is a WizardHaven at the time that the agent is revealed, and the Weathertop card is included in the series of sites through which the agent moved, Juoma’s movement is illegal. It doesn’t matter if Weathertop wasn’t a Wizardhaven when he moved there, because cards don’t have “memory”; the only thing that matters is that one of the sites to which he moved is a Wizardhaven now. Juoma is discarded and all site cards associated with him are returned to my location site.
Example B:
Turn 1. I play Deallus face-down; she is considered to be at any of her homesites.
Turn 2. My opponent plays Rangers of the North at Bree, and then plays Mischief in a Mean Way on Bree during his site phase.
Turn4. I have Twisted Tales in my hand, so during my opponent’s next movement-hazard phase, I reveal Deallus at Bree in order to play Twisted Tales and discard Rangers of the North. Bree is currently a WizardHaven but Deallus hasn’t moved there, so there is nothing illegal about the agent’s movement (or lack thereof).
Note that this digests overturns ICE Rules Digest #94 Q2.