A/N: Post "Predacons Rising". Same continuity as "With a Side of Rust", but much earlier chronologically.

Chapter 1

"He's too reserved; it concerns me," Optimus had said.

"We must make greater efforts to make him feel he is one of us,"Optimus had said.

"Every member of Team Prime is part of our family," Optimus had said.

Ultra Magnus had so many objections that he could have filled a thirty-page report with them, standard margins, single-spaced.

"Of course, Optimus. We must make him feel appreciated," he'd said. "I'll take Knock Out along on my next mission."

Now here they were in the middle of nowhere. Two mechs. Two lean-tos. And a strut-deep silence, broken only by the constant drum of acid rain on the thick silver tarps and the quiet hiss of raindrops pitting the metallic ground.

The low cot creaked as Ultra Magnus drew his legs up with a grunt to avoid the liquid seeping under the edge his shelter. He looked out. Though the grey veil of rain, two red optics were fixed on him.

Ultra Magnus watched them until they looked away.

Optimus had suggested bringing Bumblebee as well.

"Not only will his field skills be of use, but out of all of us Knock Out seems closest to him," he had said.

It was true. Knock Out relaxed around the scout, even teasing and bantering with him. The Decepticon was close to Bumblebee.

Far too close.

Ultra Magnus told Optimus he felt one-on-one bonding would be most effective. And that was that.

"Keep up, soldier." Ultra Magnus turned around to look down the hill at Knock Out, who had once again stopped to grimace at the scratches on his legs and pick copper brambles out of his joints. "I expect a better pace from a mech who values speed as much as you do."

"Yes sir." His tone was not quite disrespectful. But his tight smile hovered close to a grimace as he tramped up the hill, the vegetation adding more shallow scratches to his legs.

Despite the night-rains, the days were muggy. The land shimmered with heat, hazy and oppressive. Knock Out's frame, being smaller, rose in temperature more quickly; his fans whirred constantly. Sometimes he muttered about the sun or the rain or his scratched up finish, but for the most part he was silent. Much quieter than at the base, where he hovered at the edge of conversations, throwing in a quick, upbeat comment here and there.

He rarely contributed anything of substance, Ultra Magnus had noticed, and never offered any kind of disagreement. It was suspicious.

His silence was suspicious too. But maybe he was only too tired to speak. Ultra Magnus reached out as the red mech stumbled on a sandy hill, catching him by the pack between his shoulders and pulling him upright. Knock Out jerked away so hard he almost lost his balance again.

"I don't need your assistance, Commander," he snapped. "I am perfectly capable."

Ultra Magnus watched the perfectly capable mech nearly fall on his face twice more on the way up the hill.

At midday they stopped to refuel. The land was flat now, the shrubs smaller. Even the two mechs barely had shadows as the sun blazed straight down.

"Watch your energon supply, soldier," Ultra Magnus warned.

Knock Out muttered something inaudible and took another long pull on his hydration pack.

Normally they stopped about an hour before sunset, but the third day Ultra Magnus pushed the pace and didn't stop until well into dusk. It was a risk, but they had become adept at setting up the lean-tos quickly and he wanted to reach their goal by the next morning.

They were lucky. The rain held off while they found a campsite, while they shrugged the packs off their backs, even while they set up the shelters. Knock Out folded out his cot and sank onto it with a grateful groan. Ultra Magnus had to admit it felt good to sit down. He watched as the Decepticon pulled his leg onto his knee and began picking debris out of his pede joints with his long, thin fingers.

"Tomorrow we'll reach the Traxian Heatsinks," Ultra Magnus said. Knock Out didn't look up, but he did nod. "The plates underlying the dunes are thin and prone to collapse. You, being lighter, will take point, taking readings with the scanner as you go."

"Lucky me, leading the way," Knock Out said. His voice was almost cheerful, but it had a mocking edge to it too. Ultra Magnus chose to ignore it.

"You will wear a safety harness," he continued, "and I will pull you back if you run into trouble. Any questions, soldier?"

"I'm not a soldier." Knock Out plucked out a pebble that had been wedged behind his toe hinge, grimaced at it, and flicked it away. "But I do have a question, as it so happens. What's the point? If we know it's full of sinkholes, why even go in?"

"If we can find a stable path through the area, we may eventually build a road through it to Iacon."

Knock Out stilled in the act of drawing a small jar from his pack. "Well, of course," he said, soft and poisonous, "we simply must plot a route to Iacon."

Ultra Magnus watched as Knock Out resumed, pulling out the jar and rubbing some kind of ointment on his pedes. Iacon had been Cybertron's capital city, but also an Autobot city. The Senate's city, the Prime's city. And the only genuine, vehement argument Knock Out had been involved in since joining the team had been over which city should be renovated after Praxus.

"It has to be Vos or Kaon," Knock Out had said. "Or nothing has changed."

Ultra Magnus' frown deepened as he began cleaning the rubble out of his own massive feet. He wished Optimus were here, or at least in comm range . . . But if wishes were horsepower, all mechs would win. He shoved the thought away as he massaged his pedes. Thin, brittle flakes of metal broke off the exterior casing. He grimaced. The damage from the acidic residue in the soil made his feet ache.

"You know," Knock Out said abruptly, "that I'm a medic." Ultra Magnus lifted his head to find the smaller mech staring at him with red optics that were intent, wary, and even a little aggressive.

What was Knock Out's intention in stating the obvious? Was this a criticism of his inclusion on the mission, which was hardly a medical one? A reminder that he had helped repair Magnus after that Predacon attack? Was he trying to imply that Magnus owed him? Was it a threat? There were rumors about Decepticon medics . . .

Ultra Magnus said, "Yes, I know."

Knock Out stared at him a moment longer, gave a sudden snort, and rolled over on his cot.

An hour later it occurred to Magnus that Knock Out might have been offering, in an oblique way, to tend to his damaged pedes. But the acid rain was pouring in sheets between them by then and Knock Out still had his back to him. And so the offer went unanswered.

To be continued . . .