The Riddle and the Ring

"[...] "Quite so!" the stranger returned emphatically. "That is altogether my affair. Well, what do you say?"
Barry kept his face serious with difficulty. "Say?" he repeated. "Why, I accept, of course. I'd be a fool not to."
The unknown arose briskly.
"Good!" he said. "Suppose we take a stroll outside. This place is getting close."
Without question, Lawrence followed him out into the great vaulted space. What was the fellow going to do? How was he going to escape carrying out his side of th...