This encounter may be used on the road or in a town - either one the PCs are visiting on their way to another destination, or it may come to a more permanent home base.
Background
The Lunar Lands has no shortage of cults that venerate the divine powers, and each cult has its own roster of saints, myths, and important events in its history. Even generations after the fact, the lives and deeds of gods and holy men are remembered by relics - whether those be remains of saintly bodies, devices through which miracles were worked, or those objects that came into contact with the gods themselves. These relics carry traces of divine power, imparting the blessings of the gods upon those who possess them. Their powers vary, of course, but they may range from repelling evil to curing sickness to granting good fortune, and everything in between.
Naturally, this has made the trade - and in some cases, forgery - of relics a lucrative underground business. A shrine or temple that claims possession of a relic may draw pilgrims seeking its blessings, and the very connection to the Heavens that relics bring lends legitimacy to the clergy overseeing them. So naturally, there are some who would do anything to get their hands on one. No priest is going to publically condone such illicit activity concerning holy things, of course. But even the most outwardly pious may find the draw of fame and power too strong to resist...
The Encounter
The PCs may come into contact with the relic trade through an encounter with a traveling shrine - one way or another, they will come across a monk driving an ox, pulling a cart on which is erected a small wooden chapel garlanded in flowers and gold leaf. Seated within this chapel is a gilded reliquary depicting a bust of
Saint Hilda, a figure revered by the cult of Marseah, the goddess of mercy. In life, Saint Hilda was known for her ability to work miracles and cure blindness and lameness in the faithul, and long after her death, that power lives on in her relics. The PCs may be traveling on the same route as the chapel and pass it on the road, or they may be in a town where it is being exhibited to the public.
The monk, Brecharius, will explain that the reliquary contains a piece of the jawbone of the long-dead saint, and that some of her power still lingers in the old bone. He claims that those who kneel before the relic and recite a prayer will have good fortune, and those who touch it will be cured of illness. Anyone can pray to the relic free of charge; he charges 1 SP to open the reliquary so it can be touched, insisting that such money is to be used as a donation for the upkeep of his monastery.
There is no mechanical benefit to doing this, for the "relic" is little more than a piece of mundane bone (in fact, a DC 25 Medicine check will be able to determine it is not even from a jawbone at all, but a scapula). Brecharius will deny any allegations of fraud in public, going so far as to claim the accusers dishonor the gods by casting such doubts on a holy man. However, if the PCs have treated him politely enough to earn his trust, and if he sees them as capable of such a task, he will take them aside to speak to them privately at the first opportunity to explain:
Brecharius is, in fact, aware that the relic is a fake - but he has not forged it out of greed or malice. Rather, the real relic is claimed by Sister Closinde, a nun who oversees a temple a few days' travel to the north. She does not allow anyone to see the bone or take advantage of its properties. Brecharius doesn't enjoy having to con people out of their money to make ends meet, but he feels that the jawbone would be better served out for the people to revere and to take advantage of the healing properties of, rather than being locked away in a temple vault. Should the PCs seem the type to accept such a mission, he is willing to pay 500 GP to the party if they can break into Closinde's temple, steal the jawbone, and bring it back to him - by whatever means are necessary.
Closinde is unwilling to part with the jawbone - she is a devout follower of Saint Hilda, seeing her as a most noble patron of healers, and sees it as an honor that she would be entrusted with the relic. So too, she feels that it is safer to keep the jawbone under lock and key, fearing the greed of those who would wish to use its powers for their own gain. In her eyes, it is better that the relic never be used at all than to be used to line mens' pockets.
Closinde's temple isn't the largest, but it has a respectable staff, with eight other nuns and initiates (stats as commoners) living in its quarters, and four armed guards on the premises. The guards will patron the exterior of the temple and hold the gate, but will not fight inside the temple unless provoked, as they believe in the holy right of sanctuary, which states that no one may come to harm under a temples' roof. They expect others to feel the same - but those who would attack them or others first are, of course, ungodly ruffians to be put down at all costs.
The jawbone of Saint Hilda is contained in a modest chest in the undercroft of the temple, so as to look inconspicuous to would-be robbers. Ideally, it should be hidden among several largely identical chests, so that searching for the right one would take valuable time and potentially attract unwelcome attention. The chest is also locked, requiring a key that one of the guards carries on his belt, or a DC 12 DEX check using Thieves' Tools to pick the lock.
Further Developments
Should the PCs retrieve the jawbone and return it to Brecharius, he will reward them as promised. However, the real relic does indeed hold the power attested to it - once a day per user, one can say a prayer while touching the relic to cast lesser restoration on themselves. Some PCs may wish, then, to keep the relic for themselves to make use of its powers.
If so, they will find there are two complications to its use. For one, the jawbone is a holy relic sacred to the cult of Marseah, and the goddess will not tolerate its use for ill. Any party that possesses the jawbone must abide the tenets of Marseah - showing mercy to foes who surrender, always entertaining hospitality, providing charity to those in need of it whenever possible, and never demanding compensation unless it is offered to them first. If they do not, Marseah will be angered that a relic of her cult is in the wrong hands, and she will exert her wrath against the party - either subtly through steering them into misfortune (ideally, they should be directed toward scenes that remind them of their failings and those who suffer by them, such as encountering beggars, lepers, or the downtrodden), or, if that fails, calling down plagues and disasters.
Furthermore, even if the PCs are model Marseans, if Closinde survives the heist, she will surely learn of the theft, and she may dispatch agents of her own to try and retrieve the jawbone. For that matter, Brecharius might realize, after a few days go by with no word of the relic or the party's whereabouts, that they have deceived him, and he might look for another band of able-bodied and unscrupulous folk to steal it back. The PCs have entered the relic trade now, and the relic trade is a far deeper and more cutthroat world than one would think!