In point of fact, it wasn't until the next day at lunch that Spock saw the doctor.

Spock had spent his evening engaged in a chess match with the captain and then Bones had been occupied all morning with routine physicals – a seemingly never ending task given over four hundred crewmen all needing check-ups once every three months. At least the majority of those could be covered by the nurses or he'd never leave sickbay.

As Spock noticed the doctor enter the messhall he considered how best to phrase his enquiry.

Jim saw McCoy as well and waved him over.

"Bones!"

The doctor grinned as he saw them and headed over with his tray.

"Morning Jim. Spock."

"It is no longer morning, Doctor," Spock pointed out immediately.

"It's before lunch ain't it?" McCoy shot back. "That makes it morning in my book."

"To the majority of the ship however, it remains afternoon."

McCoy shot a 'save-me-from-pedantic-Vulcans' look at Jim.

"Guess there's no need to ask if he's feeling any effect of that powder. He's acting just as annoying as usual."

Jim frowned at him which confused the doctor somewhat but he was immediately distracted by Spock.

"I was meaning to ask you about that very subject Doctor."

"Oh?" Spock had McCoy's undivided attention now. "Feeling some effects?"

"I am troubled by no more feelings than usual-"

"Which is to say none," McCoy interrupted with a scoff. Spock merely arched an eyebrow at him.

"I was however curious whether you had any theory of the powder's symbolic origins. Given the wealth of Terran myths with inexplicable and illogical significances."

"Gentlemen-" Jim spoke unusually cautiously and neither man paid him any heed.

"Just 'cause something doesn't have a logical explanation don't mean it's valueless."

"I did not say that… although the 'value' of the Fesarian powder could certainly be debated."

"I know what you were gettin' at Spock. For a race priding itself on infinite diversity you don't half enjoy disparaging my cultural traditions."

"Whiskey cannot be considered a cultural tradition."

"Gentlemen!" Kirk's voice carried an unquestionable urgency now and both men looked at him. "You're glowing!"

Both officers simultaneously blinked before turning and looking at each other.

As they finally brought their attention back to their surroundings, two pairs of eyes widened in undeniable surprise.

Although 'glowing' was an inaccurate term, it was obvious what the captain was referring to. Each man was surrounded by a shimmering, glitter cloud. As if a cloud of tiny water particles were catching light to produce a rainbow.

Except the colour was different around each of them.

McCoy was sat amid a ruby red haze while Spock's was emerald green. They were drifting together in a cloud rising above the table, reminiscent of old Earth fireworks.

"What the hell?" McCoy gaped.

"Fascinating," Spock commented. "I would have to conclude this is linked to our partaking of the Fesarian powder."

"The powder you declared had no practical application?" McCoy glared.

"Bones," Jim admonished swiftly before switching into Captain mode. "It started forming while you sat here. At first I thought it was my eyes playing tricks but it got stronger until…" he gestured. His hand waving dispersed the mist causing it to dissipate further.

"It is being cleared by the air management system," Spock noted.

"But where did it come from?" McCoy wondered, watching the sparkles fade.

"I think you two better head to the lab and run some tests," Jim ordered.

"I already ran a bunch of tests!"

"Really Doctor?" That damned eyebrow rose again. "You were not satisfied with my initial analysis?"

"And it looks like I was right to have doubts doesn't it?" McCoy challenged. "Unless you believe it's a coincidence we're lighting up like sparklers after sniffing some damn alien powder."

"As I recall it was you who suggested we should not insult our hosts by refusing."

"I meant don't insult them by accusing their customs of being pointless!"

"I did not accuse them-"

"Ah gentlemen?" Jim interrupted for the third time in a tone of deep amusement. His officers looked around to see that their colourful mist had returned.

"God dammit," Bones muttered, pushing himself up.

"I believe it would be prudent to investigate promptly, Doctor," Spock suggested as he too stood. McCoy eyed him speculatively but then simply nodded and led the way out. Spock followed with a brief nod to Jim

Jim sat and eyed the mist thoughtfully. Then a broad grin split his face.

This could get interesting.