Jack slowed his pace as he approached Daniel's office. Daniel's office. He shook his head and wondered whether he would ever be able to think of it as anything else. He stepped inside and rapped on the door to announce his entry. Teal'c and Jonas looked up from their perusal of the survey reports. He leaned forward, resting his elbows on the central workbench and clasped his hands over the strewn photos. He nodded at Jonas. 'What have you found?'

'Not much, Colonel.' Jonas admitted a little forlornly. 'We've gone over SG15's original survey report, the initial MALP readings and these,' he waved at the aerial photos he was examining. 'As you can see there's nothing but trees.'

'Ah, trees.' Jack sighed, propping up his head on his hand. His eyes scanned the photos. 'Nobody reported any life?'

'SG15 noted a small mammal.' Teal'c reported solemnly.

'I know, they said it looked like a rabbit.' Jack supplied almost absently. He caught Jonas's curiosity. 'It's an Earth animal.'

'Oh I know, Colonel,' Jonas said hurriedly, 'I was just wondering how you knew about SG15's…'

'The briefing.' Jack returned brusquely.

'Of course.' Jonas was eager to move the conversation on and disappointed he didn't have a lot to add. 'But that's it.' He sighed. 'There's no sign of a settlement or a nomadic tribe within the immediate vicinity of the Stargate.'

'Neither SG15 nor SG2 encountered any signs of an indigenous people during their time on the planet, O'Neill.' Teal'c added.

Jack absorbed their words with a nod. He hadn't expected anything different. 'Any caves?'

Jonas looked at Jack quizzically. 'Yes, there is a cave formation in the mountain range to the West of the Stargate.' He shuffled through the photos until he found it. 'You can see what looks like an entrance here.'

Jack nodded.

Jonas smiled broadly and pointed at Jack with his pencil. 'You knew about the caves because you did the briefing, right?'

'Actually, no.' Jack denied. Jonas's face fell in response and Jack lips twitched as he suppressed a reluctant smile. 'Doctor Jackson told me.' He explained as he straightened.

'He's awake?' Jonas checked, leaning back in his chair and propping a foot up against the bench.

'He's awake.' Jack confirmed evenly. 'He claims he was attacked by a group of Unas.'

Teal'c's eyebrow arched.

'Unas.' Jonas said, twirling the pencil between his fingers as he turned the information over in his head. 'Well, that might be the reason why we haven't come across any sign of life.'

Jack looked at him blankly. 'What?'

Jonas's eyes leapt back to his team leader's. 'According to Doctor Jackson's journals, the Unas he encountered lived in caves.'

'So?' Jack countered.

'Well, if they're out of sight within a cave dwelling…'

'It would explain why we have not seen any evidence of their presence.' Teal'c finished.

'OK,' Jack allowed, 'but why haven't any of our guys come across any signs of them hunting or gathering or whatever it is Unas do.'

'Because we've scouted in the opposite direction to the mountain range.' Jonas answered. His stool clattered as his foot hit the floor. 'Here.' He grabbed an aerial photo and showed it to the Colonel. 'Our teams have surveyed here.' His pencil circled an area to the East of the gate. 'These caves are towards the West.'

'I don't know…' Jack said doubtfully.

'I agree.' Teal'c replied. 'It is unlikely that the Unas would not have investigated our trespass into their territory.'

Jonas nodded a little. 'Doctor Jackson did note they were very territorial.' He allowed.

Jack sighed heavily. 'So, we have no way of knowing if he's telling the truth.'

Jonas frowned confused. 'It's in his journal, Colonel. Why would he lie?'

'Not our Daniel.' Jack shot back. 'The other Daniel.'

'You are referring to the Doctor Jackson in the infirmary, O'Neill.' Teal'c cut in.

'Yes!' Jack pointed at Teal'c. 'Him.'

'You think he was lying about the Unas?' Jonas asked concerned.

'I don't know.' Jack admitted. 'It would just be good if there was some proof…' he gestured at the stack of photos, 'in that.'

'What exactly did Doctor Jackson say happened with the Unas?' Jonas leaned back again, tilting the stool onto two legs.

'He said he was on his planet, watching the Unas.' Jack said. 'He was there doing an anthropological study alone.'

'That is most unlikely.' Teal'c's words were coated with his surprise.

Jack shoved his hands into his pockets. 'Apparently, he went there after his second wife died.'

Teal'c's large brown eyes widened. 'I see.'

'Anyway,' Jack looked at his old friend, 'he says he was attacked when he was on his planet and he ran into the caves to get away from them. He says he backed up against a wall and then he blacked out. When he came to he was alone and he headed for the Stargate to get help. Blacked out again on the way there.'

'Maybe the Unas only exist on the planet in his universe.' Jonas mused out loud. 'After all, that would account for their presence there but their absence here.'

'Maybe.' Jack allowed. 'Either way we can't go back if there's the slightest chance there are Unas on that planet.'

'Agreed.' Teal'c said firmly.

Jack exchanged a look of complete understanding with the Jaffa. The Unas were too strong and too dangerous for them. It would take a lot for them to kill a single Unas never mind a tribe. Jack still considered it a minor miracle Daniel hadn't been killed by the Unas when he'd been captured by one.

'What if we have to go back?' Jonas asked. 'I mean, Doctor Jackson isn't really dead here, right? So, there's a possibility this other one could suffer entropic cascade failure.'

'Carter said the same thing.' Jack admitted. He shrugged. 'We'll just have to cross that bridge if it happens.'

'What if he doesn't?' Jonas continued.

'Doesn't what?' Jack asked impatiently.

'Suffer the cascade failure.' Jonas clarified. 'What will happen to him?'

'I don't know.' Jack snapped, his patience exhausted. He held up a finger to prevent Jonas from replying. 'I have to go and report to Hammond.'

'I will come with you.' Teal'c offered. He rose gracefully and the two men turned for the door.

They walked in silence to the elevator and stepped into the relative privacy of the cramped compartment.

'You are disturbed, O'Neill.' Teal'c clasped his hands behind his back.

Jack shot Teal'c a look.

'You do not trust this Doctor Jackson.' Teal'c noted.

'It's not that I don't trust him,' Jack argued, 'it's just that I, uh, I' he stumbled to a halt and watched as Teal'c's eyebrow rose knowingly, 'it's just that I don't trust him.' He mumbled. He sighed deeply as he stared up at the floor indicator. 'He's not Daniel, Teal'c.'

'No, he is not.' Teal'c confirmed.

Jack risked another look at the Jaffa and relaxed at the calm understanding he found in the Jaffa's heavy features. 'Only reality of consequence stuff?' Jack said lightly.

Teal'c nodded. 'He is not our friend, O'Neill.'

Jack considered the Jaffa's words and nodded slowly. 'That's what I'm afraid of Teal'c.'

'But were our counterparts not his friends in his universe?' Teal'c asked.

'I don't know,' Jack replied slowly, 'but he's on a planet grieving alone for his dead wife. What does that tell you?'

Teal'c breathed in deeply and nodded. 'Perhaps he is no longer friends with our counterparts. Perhaps we had a hand in the death of his wife.'

'He forgave you for Sha're.' Jack pointed out ruthlessly.

'We have no knowledge whether this Doctor Jackson did the same.' Teal'c said firmly.

Jack acknowledged the truth of that with a nod. 'He was definitely holding something back, T. I could sense it.'

'Then we shall have to be vigilant.' Teal'c murmured.

'This is going to be rough on Carter.' Jack spoke aloud without thinking and he darted an anxious look at the Jaffa.

Teal'c was looking up at the elevator ceiling. 'She misses Daniel Jackson.'

'Yeah.' Jack sighed. He rubbed his hand through his grey hair rapidly. 'She's not the only one.'

Teal'c tilted his head; the light catching on his gold emblem. 'Indeed.'