Charlotte peeled open an eyelid. Yes, that was the right way to describe how she opened her eye, as she needed to use a forefinger to gently pull her upper eyelid away from the lower. It appeared stuck fast.

The eye she had opened was struck by bright sunlight streaming in from the window, and she blinked rapidly, hoping the sky would cloud over in the time between blinks. It didn't.

She appeared to be lying on her front, a position she rarely slept in, believing it to be damaging to the skin and destined to end in long-term unhappiness à la unsightly wrinkles. What was also disturbing was the taste in her mouth, which could only be described as...absolutely disgusting. Almost as if she hadn't brushed her teeth for several days.

And Charlotte always, always brushed her teeth before going to bed.

A rapid inventory of other symptoms. Headache? Check. Heartbeat pounding loud and clear in her temples? Check. Faint sense of nausea revealing itself in the form of a gurgling belly? Another tick. This could only mean one thing: a hangover.

She hadn't had more than a glass or two of wine on any occasion in the last ten years. Drink—especially the demon wine that so many of her fellow forty-somethings fell victim to—was dreadful for the complexion. It gave you wrinkles, blotchiness and puffiness around the jaw. And then there was what it did for your metabolism, the stomach and its correlation with cellulite. Charlotte could always tell the forty-something drinkers a mile away, and she despised them for their lack of willpower.

What the hell had been in that glass or two of wine she must have had last night? The thing was, she couldn't remember having a drink last night. It had been a Saturday. That was her spa night, the night she did face masks, nail varnish, all-over dry skin body brushing, and the encasing of fingers and toes in cotton gloves and thick, luxurious moisturiser. All the better for preserving the soft, smooth quality of one's carefully nurtured skin.

A glass of wine would undo everything her spa night was supposed to achieve It spelt the difference between waking up with smooth, even skin or waking up with blotchy cheeks.

Having run through the reasons why she would not have had a drink last night, Charlotte felt a wave of guilt crash itself on the shore of her barely-there consciousness. Vanity, Charlotte! Of course, she wouldn't have had a glass of wine last night. Ed had been away on a golf trip, and she was on her own with the children, who might have needed to be taken to friends' houses. Or could, heaven forbid, have needed rushing to A&E following a terrible accident.

The mere thought of the hypothetical accident sent shudders down Charlotte's prone frame. She didn't do irresponsible drinking, and certainly not as far as the little cherubs were concerned.

Speaking of cherubs, where were they?

A mobile phone had been buzzing beside her for some time, so she rang the answer machine. A male voice boomed out.

"Janey, Janey! Wakey-wakey! Or are you still awake? That was one ripsnorter of a party, and it was all going on when I bailed. Love ya, baby. Call me."

Who was Janey? Interesting too that her mystery caller had an Australian accent.

Charlotte pushed herself up from the bed slowly into a cobra position. The one eye that had been opened was joined by the other. It was an equally painful process to widen that one too. Both orbs slowly took in their surroundings.

They were completely alien to her. The incredibly bright sunlight streamed in through two French windows, one of which was open. The bed Charlotte found herself on was a double—so far, so good—but it lacked the matching bedside cabinets she had picked out from Habitat when she redecorated the bedroom. And the sheets on it bore no resemblance to the Laura Ashley honeysuckle set that she'd treated herself to as an anniversary present last year.

She felt the sheet between her fingers with distaste. Polycotton by the feel of it, and bright green. Immediate surroundings processed and still unrecognised she looked around. The walls of the room were a lighter green with what looked like silver paint on the skirting boards and the coving, and there was a collection of photos on the wall next to the door. Her eyesight wasn't up to distinguishing detail or who was in them, but they did appear to feature a lot of people grinning at the camera and holding bottles of beer.

The floor was laminated, though the sunlight picked up plenty of dust and she noticed a few sticky brown marks. A quick glance down to her right fixed on a bottle of Jack Daniels lying on its side and two bottles of Coke also sideways-positioned.

Was this a teenager's bedroom, she wondered to herself. The sunshine coming in through the French windows had intensified. She reckoned it had to be almost midday.

She pushed back from the cobra position—murder to keep going with the intensive care-grade hangover she was entertaining—and swung her legs off the bed. She wandered through an unfamiliar corridor to a living room which had a kitchen area contained in one corner.

She opened the fridge. Its only contents were a half-full bottle of wine, some beers and several cans of Diet Coke, a drink Charlotte never touched because of its evil global identity.

Needs must, though. Her thirst raged on. She popped the tab on a can, draining it in seconds, ice-cold and delicious. That immediate problem taken care of, another problem presented itself. Charlotte's belly gurgled ominously once more. She bolted back out into the small hallway and the room on the left. Wrong, a cupboard. The room on the right, then and she bent over the toilet, furiously spitting out the saliva and then vomit that flooded her mouth.

A few minutes later, she felt safe enough to sit back from the toilet—which, like the rest of the flat, badly needed cleaning, oh hell the thought of that dirty—Charlotte was sick once more, heaving and spewing three or four times before the urge finally left her. In the detached part of her brain, she noted that she had brought up foods she didn't remember eating. The forensic detective in her noted regurgitated potato chips and carrots. But then, vomit always had carrots in it, no matter what you'd eaten.

She leant against the shower door and waited for her pounding heart to slow down. Mission accomplished, she stood up as slowly as she could and found herself face to face with the bathroom mirror.

Holy cow!

Blotchy skin, bloodshot eyes and make-up that hadn't been scrupulously removed the night before. The spa night was beginning to look like a figment of her imagination.

That aside, the face that stared back at her from the mirror was not the face of a well-preserved woman in her early forties. It was the face of someone in her early twenties, tall, honey-blonde and tanned. Charlotte's dark petite-ness had been re-worked completely. Despite herself, Charlotte found that she couldn't take her eyes off the face in the mirror, screwing up her eyes and sticking out her tongue just to check if Blondie-the-reflection did it too. Blondie did.

The reflection entertained her for all of two minutes. Then reality kicked in. What on earth was going on? Here she was, in a strange body and in a flat she didn't know. The hairs stood up on the back of Charlotte's neck. Well, a neck, it wasn't Charlotte's. The low level of unease she had awoken with intensified into full-blown panic. Where am I? Where are the kids? What has happened to me?

She decided to explore the flat for further clues. The French doors opened onto a small balcony, where there were two upturned chairs and a table with an overflowing ashtray. A pair of flip-flops (male? Size eleven?) and some strappy sandals lay abandoned next to the table. The brown sticky stains had made their way out here too, forcing Charlotte to pick her way gingerly between marks.

She did not recognise the view from the balcony. The flat was seven or eight floors up. It looked out onto a broad street lined with palm trees. Charlotte was wearing an over-sized tee shirt she assumed was a man's. By now she had given up mentally tallying up the things she didn't recognise but out here on the balcony she realised she was not in the least bit cold. Post-hangover bodies give off their own heating system courtesy of detoxification, but last night when Charlotte went to bed in her London home, it was early April.

And here she was standing outside in April and not cold at all. As she held out her palms and gazed upwards, she realised she would need sunscreen if she stayed out here any longer.

She gave up on the balcony and wandered back into the bedroom, picking her way between the sticky stains as she moved towards the doorway. It led out to a small corridor, off which was a large living area, the room she hadn't looked at properly earlier while dealing with her thirst and subsequent vomiting. The living area had the same lack of cleanliness standards as the rest of the flat. A large squashy sofa in cream leather sported dubious stains. It faced a giant-screen, dusty TV. Charlotte scrunched her nose up at that. She hated rooms where TVs dominated the space.

Shelves close to the TV housed DVDs—no books?—and the glass coffee table held a handbag that had partially spilt its contents onto the surface. Since she didn't recognise the bag, innate good manners—even in the face of the terrible confusion she was now experiencing—stayed the hand that desperately wanted to rifle through it.

At the edge of the table, she noticed...No, no, no. On top of a lot of disturbing observations, that observation pushed too hard at the borders or reality. It would have to wait.

The kitchen area had none of Charlotte's usual kitchen accoutrements. No gleaming pots and pans, no neat shelf featuring cookbooks and nothing that looked family-related.

She wandered back to the sofa and the glass-topped table. Some of the contents that had spilt out of the mystery handbag handily included a ballpoint pen, and she retrieved a sheet of paper from a notebook on the table.

Sitting down on the grubby sofa and using one of the DVDs to lean on, she wrote her name at the top of the sheet.

"I AM CHARLOTTE." Emphasis on the 'I am'. I seem to be in a flat belonging to someone called Janey?

What next?

Country? Possibly America, California, or maybe Australia.

A frenzy of writing took over. I don't know where I am; I don't know what has happened to me, I have woken up in a place I don't know or recognise. I seem to be in the body of a woman in her early twenties. I've got a hangover of gargantuan proportions, not to mention...

A quick glance at the table once more, the handbag and—yes the other stuff.

...possibly a cocaine addiction. What on earth, what has happened to me, what the fuck??????

Writing the word 'fuck' created a teeny-tiny temporary sense of relief. It was language Charlotte didn't usually allow herself to write as cherubs could find it. The paper tore as she pressed the pen hard into the f and the k.

Temporary relief over, Charlotte burst into tears.

"Oh Ed! Where are you—where am I, and where are my children?"