They had dropped in to see if Whitey had arrived home safely, supposing that he had started for home when he left the Star Circle.
When it was learned that Whitey wasn't at home, and no one knew where he was, Mr.Sherwood had his surprise, and it wasn't pleasant.

And Bill Jordan looked crestfallen.

They had talked it over till late, and decided to start a search for Whitey in the morning.

Then, when Whitey, clad in a large night-shirt and riding a half-wild pony, came to summon the vigilantes--well, it seemed a time for surprises.
The men hastily dressed and armed themselves, summoned all the others on the ranch, and saddled their horses.

While this is going on, at the risk of telling you something you already know, a word about the vigilantes.
In the Old West various bodies of men were formed to clean up the wilder elements.