"I am experiencing difficulty in maintaining a position of rest."

"So, in other words, you.... can't sleep."

"Indeed."

"Any idea what's causing it?"

"It has to do with.... biology."

"Biology?" In an instant, Kirk was ready for action, 0130 or not. He'd heard these momentous words before and he was hard as a rock in seconds.

"Biology," Spock repeated dryly. "Apparently, even the minor amount of caffeine in decaffeinated coffee is sufficient to disturb the Vulcan sleep cycle."