The party are contracted by a noble to safeguard a vault during a local festival. (Whether the party arrive in town and find the job, or whether they are sought out for the job is entirely up to the GM and their knowledge of how readily they jump on plot hooks.) It is explained that the noble of the house (Geoffrey Wyson Esq.) has been invited to a grand ball as part of the local festival, but he has recently heard of vaults being emptied during festivals. Other nobles and well-to-do people have hired extra security for the night and Wyson has decided to do the same. Upon expressing interest, the party are shown around the home. They will, in course, be introduced to Wyson before being given the terms of the contract. Most notable among these is the stipulation that they'll be required to leave their own valuables in the vault to ensure they have a vested interest in protecting the contents.
Provided the party accept the contract, they will briefly be introduced to other members of the gentry. Seeing the increased security, one visiting noble, introduced as Lady Eloise, asks if she might store some personal possessions in the vault as well. The lodgings he has taken in town lack anything secure enough, but continuing to carry them on her person seems to be equally ill advised. Wyson happily agrees and then leads his friends to the ball.
Around midnight, the item Lady Eloise asked to store will activate and attract anything made of gold or silver and any loose precious stones together into a human form. Although the players may not have worked it out, the item was in fact a seed for a Trash Golem. Once it has built its body, it will proceed to break out of the vault. If the party have stationed themselves anywhere but directly next to the vault, then they will have to identify the crashes coming from downstairs as being different from the general cacophony of the festival. This is a relatively easy task, but there's always the possibility of failure.
If the party have taken up watch around the vault, they can skip noticing the golem breaking out and jump straight to combating it.
Having discovered the golem, the party can then take whatever action they deem appropriate. At the first sign of violence, the golem will immediately flee, crashing through doors and running through the streets. The players are perfectly welcome to give chase, but the golem will not fatigue or slow down, whereas the PCs inevitably will.
Should they manage to capture the golem, via rope of entanglement, magically freezing it, or anything else they dream up, the party will be able to easily identify the golem seed in the centre of the golem's chest. Upon removing it, the gold will become inert and need to be returned to the vault manually. When presenting the seed to the noble, it will be confirmed as the object Lady Eloise left there the previous night, resulting in her arrest when she arrives.
The next morning, when explaining the situation to the noble of the house, Lady Eloise will arrive apologising for the rushed nature of her visit, but she is on a strict timetable and just wants to retrieve the valuables she left the previous night. On hearing the vault was cleared out, she will be initially distraught only to compose herself as she remembers her tight schedule. She will then leave insisting that she will be in touch to provide details for any further developments.
If the players don't immediately find Lady Eloise to be suitably suspicious, the GM can provide sense motive or spot hidden skill rolls to any character who should be able to spot a liar.
If, however, the players have it sussed and Lady Eloise is accused while she visits, she will kick up a major fuss and express nought but outrage, demanding evidence etc. At the first available opportunity she will insist the matter is settled and leave, apparently both distraught and insulted while the players carefully try to avoid any situation that would result in their arrest.
Lady Eloise will not be difficult to track. She will have casually, perhaps carelessly, mentioned which coach depot she would be departing from when she dropped by Wyson's home. Upon investigating, they will easily learn where Lady Eloise was aiming to go and will have no trouble following. Upon arriving at their quarry's destination, the PCs will find her more difficult to locate. No one will recognise her name, but a good description yields varying results and there are many haunts where she may be found.
After some further investigation, the party will be able to catch up with Lady Eloise, real name Elyn Adroit. When they find her, she will be engaged in charitable activities, providing aid to the local orphanage or delivering a large hamper of food to the homeless shelter. The players are free to make a scene at the location or tail Adroit back to her modest abode. In any case, she will give up the chase and explain herself. Adroit turned to thievery as a means of redistributing wealth to those in need and only steals from those that have gained their money from questionable practices. Wyson, for example, had amassed his fortune mining precious metals, establishing mining villages in remote locations, recruiting entire families from poverty stricken areas with promises of a better life. Once there, they find they are paid the bare minimum necessary to survive in credit notes only redeemable at the company store. By coercing families into what amounts to slave labour, Wyson made himself a prime target. Adroit defends her actions claiming she only ever steals coins and jewels, leaving her targets with plenty of antiquities to sell if they need the money that badly. She then takes the newly acquired wealth and uses it to tend to the needy, her own modest needs being met as well. She goes on to explain that ever since she learned to create a Trash Golem seed that only attracted other valuables, the good she has been able to do has increased dramatically.
After Adroit makes her case, the players can decide her final fate.