This is Part 6 of the Deadly Sins series which eventually will explain why McCoy and Spock left Starfleet after the five year mission.

What happened so far:

Doctor McCoy is mind raped on Meriah Five by Delihan, a high official of Meriah. He recovers with the help of Spock and Kirk who find out that the Romulans, foremost Commander Tamulok, have their fingers in it too. Delihan is imprisoned on Meriah for treason. (Pride)

The Enterprise answers a distress call, and finds that all Romulans of Tamulok's ship and all Vulcans from the ship that escorted them back to Romulan space, have been infected with a virus that controls their minds. Spock is affected too and under the influence of the virus he attempts to murder McCoy. In the end, everyone is saved and cured from the virus. Tamulok is beamed on board the Enterprise, and T'Plok, a female Vulcan doctor, takes residence in sickbay to help out the understaffed medical crew of the Enterprise. (Sloth)

Tamulok escapes with the help of T'Plok, who turns out to be a Romulan spy called Velal. While Tamulok manages to stay on the run, Velal is taken into custody. She admits that Tamulok is a danger not only to the Federation, but also to the Romulan Star Empire and she wants to have him eliminated. However, she seems to be unable to kill him herself. (Envy)

Kirk and McCoy beam into the Prolia Prison Complex on Meriah to question Delihan about Tamulok's whereabouts. They find out that all prisoners in that camp are infected with the virus (c.f. Sloth) and are telepathically controlled by the free Meriahns outside the prison. When the prisoners start to attack them, they manage to escape with the help of Delihan who later dies in an accident before he can tell them anything about Tamulok. McCoy manages to get an injured Kirk to safety, but cannot escape himself. Meanwhile, Spock has to decide between getting Kirk to a neurosurgeon on Starbase 3 in order to save his life or investing precious time to work out a risky plan to save McCoy. Spock decides to rescue McCoy who is then able to help Kirk. (Gluttony)

A security officer calls McCoy to the brig, because Velal is having a fever and behaving like a rabid animal. McCoy finds out she has the Romulan equivalent of Pon Farr. Suddenly the power goes out on the Enterprise and the crew struggles to find out what caused it. It turns out that it is Tamulok who wants to capture Velal who is his wife. Velal is afraid of him and she and McCoy flee into a Jeffries tube. With the help of Kirk, they manage to trap Tamulok who then beams off the ship. McCoy helps Velal with her problem, and she tells them, that Tamulok has a human woman as a wife, and a sixteen year old son on a planet in sector Z6. She suspects they can find him there. (Lust)

o0o

Greed is an excessive desire to possess wealth, goods, or abstract things of value with the intention to keep it for one's self. Greed is inappropriate expectation. However, greed is applied to a very excessive or rapacious desire and pursuit of wealth, status, and power. (Wikipedia)

Greed

His world was made up of a cacophony of sensations. Sensations he couldn't make any sense of. He had no idea where he was, there were blurs of color all around him, mostly green with blotches of brown and yellow, also some blue, but he couldn't make out any shapes. As he tried to move his head, white pain exploded behind is eyes, sharp and blinding. There was also a red pain in his shoulder, emanating into his side, his hand and fingers. Odd, since when did pain have color? He held onto that thought as he concentrated on not throwing up. Clenching his jaws, he heard a pressed hiss of air, and felt a brief triumph as he identified it as his breath, travelling through his flared nostrils. The white flash disappeared and the screaming red faded into a dirty, but manageable brown.

"S'alright, Bones, don't move, just close your eyes," he heard someone say, and he briefly wondered who that guy was and who he was talking to.

The pain retreated somewhere to the background, but he still could feel it lurking, watching him, ready to sink its teeth back into him. He tasted salty sweat on his lips, it was hard to breathe. The air was humid, just like it always was near the lake on a summer night.

He tried to clear his throat, to ease his still strained breathing, when again that all consuming pain latched onto him, filling his vision with garish colors again. There was a noise ... voices, but they sounded muffled, as if he heard them from under water. Maybe that was it? The lake near his parents' house? Had he fallen into it and was he drowning?

No, he could feel air filling his lungs, even if it was not near enough, he was still breathing, or wasn't he? He felt his heart hammering against his ribbcage and in his throat as panic overcame him. He'd been wrong, there was no air! He tried to free himself from something that was clutching him, holding him down, only to be rewarded by that crushing pain again.

"... got to stop moving! You'll only hurt yourself!"

He could make out the words of someone in obvious anger and found he was not under water at all. A person was holding him from behind, his arms around his chest in a vice grip, making his breathing difficult, immobilizing him, totally. Maybe that bastard had even broken some of his ribs, he thought, that would explain the pain.

It suddenly came all back to him in a flash: the biology project about bees, Gemma, the walk around the lake, and Brad King and his gang.

They were doing a number on him right now, cracking his ribs, breaking his nose, giving him a concussion. He would break Brad's fingers while deflecting a blow with his foot, but in the end, they'd all survive. He felt a bit of relief when he found his brain at least partially to be functioning again, although something didn't quite feel right, however, he couldn't possibly say what it was that confused him. And he couldn't breathe, dammit.

He clawed at the arms restraining him, and for a second was able to ignore the flaring pain in his shoulder. If that guy didn't losen his grip, he'd suffocate! There was no air, and it was so damned hot that the sweat was soaking through his clothes. To be pressed tightly against someone's chest, didn't help at all.

"Stop! … You're … drowning me!" he shouted as loud as he could, immediately wondering, why he'd chosen those words, he'd just established he wasn't in the water. However, he supposed the general message he wanted to convey would get through anyway. He also knew it didn't matter what he said, that asshole wasn't going to let go of him before he passed out.

He definitely did not expect what followed. The arms around him loosened, just like that. And as he was once again trying to keep himself from throwing up, something cold was gently pressed to the side of his face. It was a wet cloth, he realized, as it slowly wiped the sticky, salty sweat away from his face and lips, and then moved to his neck and shoulder which hurt, although he could feel the touches were feathery light, meant to be soothing, and somehow that was enough to make them comforting despite the pain.

He drew small, shaky breaths, ridiculously shallow, but at least they were regular, at least they were there. The bully had turned into a lifeguard, a buoy that kept him above water, kept him afloat with infinite gentleness. Oh, the power of words! All I had to do was ask him to stop.

After a few minutes of listening to his own breaths, he started to take stock of his surroundings once more. He was sitting on something soft, a couch, or a mattress, and was still leaning against the guy who had tried to suffocate him just a minute ago and who was talking in a gentle murmur somewhere to his left ear. Before he could actually focus on the words, he drifted off into sleep.