Traveling overland, as the sun sets, you and your party make camp a short distance from the road and prepare to settle in for the night when a stranger approaches and asks to share your campfire.
The aged man, Gavin Gorvenal, is a ranger and on the trail of a band of hobgoblins who have been murdering innocents in nearby towns. If the party is welcoming, the ranger offers up information on the surrounding lands and, if they gain his trust, he tells them of a crumbling fortress two days’ hike to the north where there are rumored to be lost riches and treasures.
If the group rejects his request to join them for the night, the ranger wishes them well and moves on. As the night wears on, they see his fire about a mile away.
In the middle of the night, whether or not Gavin is camping with them, the band of hobgoblins attack. If Gavin is with them, he joins in the defense of their camp and will fight as hard as any member of the party. If he is not with them, he arrives within 1d6+3 rounds of the attack; he has been alert and waiting, suspecting that the hobgoblins were nearby and going to attack.
If they survive the encounter, Gavin welcomes them to join him in seeking out and destroying the remaining members of the hobgoblin warband.