[It's supposed to be unknown and quite difficult to find, afaik.]
That response was written OOC. The first part, sure, was Alienorâs response to the vis request for the ritual to summon the spirit, nothing to do with Val Negra as far as anyone knows at Bentalone, but the second part about âwhat could go wrongâ was me as a player. The Part about Val Negra came up for Jerome, while at a library at the covenant in Toulouse which is at least few days journey so unless you went with he would not have said anything to us yet about it.
I think it was hidden by the few surviving magi so no one would go there and rouse the âFlambeau beingâ.
I'm definitely into a story to find Val Negra as a player and in character. 
It was hidden centuries ago and those what knew its location have passed into death or final twilight. I have seen games where it has been rediscovered or remembered where the SG was fond of the location. I have no particular inclination either way but it is a very big secret that a large number of magi are looking for and failing, so it isn't something you are likely to simply stumble across in a library. You know it is in the Pyranese, and the name of the river and mountain which identify its location, but that river and mountain are not currently known by that name, and even finding them will not ensure finding the covenant, and there are multiple theories as to where each of them are, as well as suggestions that the mountain is receding into the magic realm and/or that the river has been diverted or dried up.
Indeed. I did not expect it to be easy to find. I just hope that the bound correspondences is going to be a useful clue. Even so I expect decades of research.
But one question. Would the Toulouse covenant allow visiting readers to copy the collections of letters? Or sell copies? On what terms?
@Ignes.Festivus It is no secret that Astella's Garden is like a Holy Grail to him, and he hopes to find it some day. If it is ok with @Plot_Device , he and Gerard have agreed to go together if one of them ever finds a worthwhile clue. If that's the case, Jerome will mention that Toulouse has several bound corresponendences about past searches, which did not have time to study yet.
Do you mean me? Gerard would definitely agree to that. He would comment that the correspondences seem to have a use in at least pointing out dead ends. Do you have anything that could be an arcane connection to the garden? Looking for that might be a better way. Maybe something transplanted would be an Arcane Connection? (he says)
Yes, sorry. Ignes asked the question, seemingly on your behalf ...
ACs must be harder to find than the garden itself, I think. Centuries must have passed. No, all he has is the legend. I reckon we must read what we find, looking for clues, and piece them together for decades. When we are chased out from our current abode in 1207 we can set up a base in the Pyrenees ...
You indicated that this would a correspondence, but it escaped me when it proved to be non-Hermetic and outside redcap routes. If we treat it as correspondence, which is the topic? How does the mail route work? I.e. is it regular enough to work as correspondence?
It is regular enough to qualify as correspondence, but it is toward organization lore: Mystery cult of the garden of delights
Right. So I can take a season to practice the Org Lore and gain 5xp? Four as default practice + one for correspondence? Only testing ideas.
I imagine it might be plausible to gain the correspondence xp if you did a lab activity around trying to understand the spell from the casting tablet as well, trying to gain insight which was discussed previously. Seems strange practicing an MC lore before having any xp in it but perhaps the initial letters would give enough information. Also, depending on how defined Silveroak is taking the correspondence rules around "related to the seasonal activity" perhaps using profession gardener might be related. All of these are merely possible suggestions... assuming Profession: Gardner is a skill important to an MC cult around gardening.
Side note: Also, the daimon might also be a mystagogue but I have no information backing up that idea just seems a possibility to me.
I am a bit torn here. As a player I am 95% certain that the ritual is infernal and the daimon a demon. There are several reasons why that would be a natural thing for the SG to introduce in this story, in face of this character.
I am not sure just how suspicious Jerome ought to be. He does not want to sin, so some caution as to whether the ritual is sinful would be appropriate, but he has no infernal experience, so that might not be on his radar.
A pity I did not get the name of the cult in time to research it in the library.
@silveroak At some point when he is in Toulouse, Jerome sends a letter asking in detail about the cult. Is there a book where he can learn more about it? Does it have other members in Provence or nearby?
Researching the cult directly does provide some usefull information- it is a small mystery cult in northern France, very selective of whom it initiates. Minor investigations have been done by both the church and the order- the Church could find no practicing members and dismissed the cult as a fanciful story. The Order determined that there were no practicing members of the order and no practical reason to pressure the cult into joining the order. One member of the order or Praelix apparently made contact with them but had no success in persuading them to join.
This is information I gain from the correspondence or from the library in Toulouse? Or both?
The library.
Jerome is quite encouraged after the season in Toulouse, but he still wants more information. He sends another letter asking how many times the ritual must be cast to summon the daimon, and if this has to repeated every year. He also asks if he can come to Paris and study the lore behind the cult in more detail. In the meantime he bends over the big Herbam book again.
The reply is that you can summon the daimon, who will teach you how to make your impressive garden, with a single use of the ritual, but you will need to be initiated into the mysteries of the tradition before you can use the ritual. He is happy to meet with you in Paris and discuss your joining their tradition.
Then he will travel at the end of Summer, once he has had his serving of Herbam for the season, and spend the Autumn in Paris.
@silveroak Pulling attention away from Jerome and his research into the ritual for a second, how do we proceed with the vis hunt story? To recap, I already rolled and got a 3 which + area lore and intelligence adds up to a 10. If Alienor and Lutra are each searching individually, and considering Plot_Device wanted us to take along Gerard's sons, how about we take along 1 each?
They don't like to be separated 
Only one is actually helpful anyway (Magic Sensitivity) They would go with Alienor, cause Blatant Gift vs. Binding the Gift (since they're magic).