A/N: This is a crossover with the TV show Life on Mars, and I'm using the character Gene Hunt and Colin Ronson from Life on Mars.

"Interview commenced at 11:19 AM."

The room was illuminated only by the watery sunshine filtering through the blinds, casting half-hearted shadows across the cluttered desks and six people. Remus John Lupin, DCI of the Cardiff Metropolitan Police Force, sat directly opposite a young man whose trembling jaw suggested that he was barely containing his fury.

"The suspect will state his name."

The young man looked up from where he had been glaring at the desk to look the DCI in the eye. "Colin Ronson," he growled, almost baring his teeth at Remus.

"Also present are the suspect's lawyer, social worker and psychiatrist," Remus continued, unfazed by Mr Ronson's feeble attempt at intimidation. "Look at these photos, if you will, Mr Ronson," Remus fumbled with a file and pushed pictures across the table towards Colin. "Lauren Chester," he explained as Colin and his team studied the photos. "Murdered in November last year. Kidnapped, no sexual assault, starved and held for 30 hours. Strangled with bootlace."

Colin groaned at the photos. On the paper were pictures of a young woman's corpse, angry red welts marking where she had been strangled. "You're upsetting him," the social worker protested.

"Tina Mitchell, attacked last Saturday," Remus continued, ignoring the social worker. "You said 'Fight me, and you will end up like Lauren'." Reaching for his laptop, Remus said, "This is the ID picture that Tina gave us," and showed Colin a photo that was clearly of the young man himself.

Beside Remus sat a woman, her appearance punctuated by violently pink hair. She had remained quiet throughout the interview, but at this point she passed a package across to Remus. "Here is your diary. We found it in your room." He handed it to Colin, who snatched it impatiently and held it close to his chest. "From the diary – quote – 'I killed her. She's dead. I'm a killer, an ace killer'. That particular entry is not awash with ambiguity," he added sarcastically. "Dated November the fourth – the day after the murder."

"Colin's a first rate fantasist," the psychiatrist cut in.

"So let's talk about the night of the abduction, eh?" Remus ignored Colin's protectors again. "November the second."

"Hold on – November the second?" the social worker asked, rifling through her paperwork.

"That is correct," Remus nodded, drawing his eyes away from Colin for the first time.

"He was at the drop-in centre. Some kids had thrown some fireworks at him and he was distressed. We brought him in."

When Remus had no answer, the lawyer clapped the lid of her notebook shut. "I think we're done, don't you, Detective Inspector?"

"OK," said Remus, firing up his desktop and chewing his lip thoughtfully. "We'll have to go with our next best lead. The fibres underneath the fingernails of the victim. I'm pretty sure it's synthetic-"

"I think there's more to Colin Ronson." Behind Remus stood the woman from the interview room, running her hand through her hair impatiently. "Let's lean on him."

"What, and be sued for harassment of a schizophrenic? No thanks. Look, it's all in his psyche evaluation-"

"Well fuck his psyche evaluation. What happened to gut feelings?"

"Nothing," Remus insisted. He sighed deeply, and pushed his chair around to look at Tonks. "I'm gonna stand you down from the case, Dora," he told her, using the name only he had permission to use. "I think our personal relationship interferes too much."

Tonks looked surprised for a moment before dragging her hand through her hair again. "Look, forget about that. I think I might have an idea about Colin Ronson-"

"Dora, you're not working on this anymore."

"Please, I think I'm right about this-"

"Dora, no," he snapped. "We'll talk about this later, OK? Go back to work."

Remus swung his chair around to face his computer before Tonks could react and listened to her walk away when she realised it was not up for negotiation. He rubbed a frustrated hand over his face but continued to work, using his infamous ability to ignore his emotions as it suited him.

Half an hour later, as Remus shut down the computer and looked for his wallet so that he could grab some lunch, his mobile buzzed against his thigh. "Hello?" he answered, still searching for his wallet.

"Remus? It's me," Tonks replied. Remus' brow furrowed.

"Tonks? What's wrong?"

"I'm tailing Colin-"

"You're doing what?"

"I'm following up on my idea-"

"Dora, where are you?"

"I'm fine-"

"I'm calling for back up-"

"I think that-" There was a shriek and the line went dead. Remus' hands started to shake.

"Dora? Dora, speak to me," he hissed, but to no avail. He threw his phone onto the desk. "Kingsley? Come on, you're with me," he said, whirling around to speak to his DI.

They found Tonks' jacket, spattered in blood, hanging on the seat of a swing in a grotty park. Remus had been managing to keep a lid on his emotions up to this point, but seeing the jacket she had been wearing not an hour earlier broke through to him and he staggered backwards a few steps, breathing heavily. A firm hand landed on his shoulder, and a gentle voice suggested he went home.

"This is a crime scene," Remus muttered in a strained voice.

"I know. Go home, Lupin." Remus nodded and turned away.

The tears started to fall once Remus was pulling out into the dual carriageway which would lead him home. Darkness was pulling in fast and Remus' vision blurred as he wondered where Tonks was at that moment. He realised his hands were shaking when he reached up to wipe his eyes furiously.

"Oh God, Dora, I'm sorry," he whispered. A moment later, Remus realised he was accelerating straight towards a junction. Before he could open his mouth to scream, there was a flash of bright and everything went dark.

Light started to filter through Remus eyelashes, and he blinked himself awake, but the sight that met him was entirely unfamiliar. Although he was still sitting in the front seat of his car, he appeared to be in a car park. He lifted up his hand to feel his face, finding a cut across his left cheek, and sighed heavily. It was just another one to add to his collection of scars, gained during a struggle with an escaping robber years before. His face was practically unrecognisable, a myriad of jagged scars. How Tonks had ever managed to love him, Remus would never know.

The car park suddenly looked more familiar as Remus twisted around in his seat to get a better look. He recognised it as the car park behind the Cardiff Metropolitan Police Station – his place of work for the majority of his life - although it hadn't looked like this in years. The walls were covered in graffiti, construction were was being done to extend the station, and the cars surrounding Remus looked several decades ol.

A man was stalking towards Remus, who shied away in surprise when his car door was wrenched open. "You're late," the man said through gritted teeth. Remus stared at him.

"Sorry?" he asked after a beat of bewildered silence. "Who are you?"

"Your new boss." Remus' boss leaned over him to snatch a pile of papers from the passenger's seat. "And you, Mr RJ Lupin," he continued, reading from the papers. "Are late."

Remus realised that this was not his car at all as he followed the man's hand to the car seat, an ugly pattern adorning them rather than the ordinary black he was used to. He tumbled from it, taking a shaky breath as he brushed off his clothes. His clothes were not the shirt and tie he had pulled on that morning, but a long, heavy overcoat and a pair of jeans.

"Come on, then," Remus' new boss said gruffly, walking toward the police station. Remus scrambled to keep up with him, following him through the building.

"What's going on?" he asked, an odd feeling of nostalgia falling over him as he was met not by a tidy office with smart men and women looking important as they glared at computer screens, but by a room filled with smoke and towers of paper teetering on desks.

"I'm Gene Hunt, DCI of this office. You're John Lupin, and you've been transferred up from London."

"Guv, I think he might have amnesia or something," a younger man said from Gene Hunt's shoulder, staring at Remus with a furrowed brow.

"Amnesia?" Remus asked in bewilderment. "What's going on? Where am I?"

The unnamed man placed a reassuring hand on his elbow. "You're at the police station."

Remus jerked his elbow away. "What year is it?"

"1981."

Remus staggered backwards and sat on the corner of a desk, massaging his forehead.

He had no idea what was going on. It was unlikely to be a prank – he had no friends who would bother making a joke so elaborate. It was possible he was imagining the whole scenario. He could remember being hit by the car. Was it possible he was now in hospital, in a coma, his subconscious bringing him back to his youth?

His instinct was to protect himself, first and foremost, to keep on his guard and in the meanwhile behave as if this was normal.

"He's fine," the guv was saying. "Shut up about the fucking hospital."

"I'm fine," Remus agreed, looking up from where he had buried his face in his hands. He was met by sceptical looks. "Honest. I've just got to get some air."

Cardiff looked similar to its twenty five year older self. The old, crumbling arcades still stood in the centre of town, although the shiny new shopping centre was nowhere to be seen. The same accents, distinctive only to the native ear, filled the streets, although the clothes people wore were clearly not from the 21st century. As Remus wandered the streets, he became more and more calm. He accepted that this was all inside his head, that he was in the hospital twenty five years in the future and reliving Cardiff as his eighteen year old self knew it.

Remus could also guess as to why his subconscious had chosen this era of his life: 1981 - the year he lost all of his friends. The year Lily, James and Peter died, all murdered by Remus' friend, Sirius Black. Once they had vanished Remus had found himself with nothing and had dissolved into loneliness for years. When he was twenty three he applied to the police training academy, and after that he worked. If he stopped to think about it (and he tried not to) there was very little to his life other than work. Tonks had been a breath of fresh air.

Remus' heart clenched at the thought of his girlfriend, and he looped back to the police station, walking as fast as his feet could carry him. Whether he was dreaming or not, he wanted to take the opportunity to ignore the agony of his real life.

"Where the fuck have you been?" Gene Hunt asked when Remus entered the office. Before he had a chance to reply, another younger man appeared.

"Guv, we've got someone reporting four murders. Husband, wife, and child. The suspect has gone missing."

Remus felt his stomach drop out from underneath him and turned dazedly to Gene Hunt. "What day is it?" he asked, dread creeping up his spine. Gene Hunt pulled a face.

"Hallowe'en. Are you sure you don't need the hospital?"