The only way I could do another Sybil and Tom story was to make it a very different universe from Perfect Delivery/Walls come Tumbling Down, but I had an idea and I hope you like it. It's a much darker tale; I may up the rating to M at a later stage, if I'm brave enough. Please let me know what you think!

If she had known then what she now knows, she would never have said it. A fairly innocuous remark, only teasingly intended, but the implication was, as it turns out, correct. If you knew in advance that your words to someone might be the last you ever exchange; what would you choose to say?

ooOoo

It's a mundane Tuesday morning and she's trying to butter toast while standing up in their galley kitchen, leaning forward and pressing against the counter as Emma squeezes behind her to reach the sink. The radio presenter says that the forecast will be fine; London is experiencing an unexpected Indian summer before autumn takes its stranglehold and the temperatures inevitably begin to plummet. Sybil munches on her toast and taps her foot to the season's catchy hit, still frequently played as people resist the changing season and sense of new beginnings that September brings.

Emma washes up her bowl and mug, leaves them to dry on the draining board. Wiping her hands on a towel, she smiles as she looks out of the window.

"It's gonna be another lovely day!" she announces with a satisfied smile and Sybil makes a verbal noise of accord, still chewing on her breakfast. "I might be late home tonight…department drinks" she continues and Sybil swallows swiftly.

"Will you be home to watch that TV drama?" she asks. They've watched the first two episodes together and agree that it's an above average thriller. It's unusual to find something that they want to see together; their different lifestyles and tastes mean that their viewing habits don't usually collide. She misses that after living with Gwen, whose longstanding friendship and similar preferences meant that they often curled up adjacently on the sofa, even if it was to berate dubious plotlines and their plausibility.

"Maybe…" Emma replies "…record it for me if I'm not back, will you and I'll watch it tomorrow?" and Sybil nods.

Her flatmate stretches, palms aloft towards the ceiling as she prepares to leave and then gives an audible sigh.

"Actually I might be out tomorrow as well, thinking about it. It'll have to be Thursday."

Sybil grins "Out again?" she teases, although in reality she's envious. Emma's short term residence in London is compensated by a far more extensive social life than she has ever managed in seven years. "You little stop out; you'll get yourself a reputation!" The words are uttered and can never be retrieved. Emma smiles and gives no hint of offence. Walking past Sybil once again, she picks up her bag from the living room and heads for the front door.

"See ya!" she calls and with that, she's gone.

ooOoo

Sybil's pressed for time and dashes to get changed. She's working in the Urgent Care Unit at Guy's Hospital this week, covering for another doctor who's on annual leave, rather than A&E at St. Thomas' which is her usual base. She's used to the variation of shift work and finds it difficult to adjust to the standard working hours that her temporary post offers. There's a parcel to send for her sister's birthday and she wonders how she's going to find the time to visit the post office, indeed how anybody who works these hours can ever run their errands around their working life. However she finds a rolled up canvas bag in her bedroom and puts the present inside, choosing to take it with her in the hope she might have the chance to take a decent lunch break for once.

Her shift is busy and time passes quickly. It's not a role she would want on a permanent basis, but its novelty keeps her interest and she appreciates the lack of urgency as she oversees the cuts and swellings, retrieves a piece of Lego from the upper reaches of a toddler's nostril and listens to the war stories of a veteran who's in denial about his Parkinsons and has burnt himself on hot tea for the second time within a week. She's in the process of referring him for additional home help when Alex, the on-duty nurse turns the 'Closed' sign with a sigh of satisfaction and signifies that the day is nearly at an end.

There's been no opportunity to post her parcel so she rings Edith as she strolls unhurriedly back to the tube station and offers apologies that her gift is going to arrive late. Stepping out at Kennington and raising her face appreciatively at the dwindling sunshine, she steps into the 24-hour mini-market and buys a tub of pasta sauce, bagged salad and bottle of wine, grabbing the final copy of The Guardian from a shelf as she passes by to the tills.

She sits comfortably on her sofa dressed in leggings and a baggy t-shirt, newspaper laid out on the coffee table and wine glass within easy reach, while she leans forward with her pasta bowl, absent-mindedly spooning it into her mouth. She enjoys the camaraderie of sharing her living space but appreciates an evening of solitude nontheless. Emma doesn't return so as 9pm approaches, she sets the TV to record the programme, but decides to watch it regardless, becoming engrossed in the storyline and laughing when it makes her unexpectedly jump. She checks her email, replies briefly to Gwen who's checking in and reporting on developments with her latest conquest.

"Don't fall for him too much – you have to come home again in February! Unless you're going to bring him back with you….?!" she types, pleased that her friend is enjoying her year's placement, but earnestly hoping that it doesn't become permanent. They've been friends since secondary school and contentedly shared a flat for over two years before Gwen was offered the opportunity to work in the Dublin office of her management consultancy firm, swapping with an Irish colleague. It had been Gwen's suggestion that Emma simply move into the flat in her place, avoiding any need for Sybil to move or find a new flatmate independently. It has been a simple and successful solution; although their friendship was never going to compete with the history she and Gwen share, Emma has proved to be an amiable companion, who offers no unsavoury habits and is frequently away at the weekends. At the placement's conclusion, she will return to Dublin and all being well, Gwen will move back in with Sybil.

There's no sign of Emma when Sybil goes to bed, so she leaves the hall light on as is their habit when one or the other is expected home. She sleeps deeply, with vivid dreams that confuse her at the time but are instantly forgotten as she wakes. Walking sleepily to the bathroom, she notes with surprise that the light remains on and wonders if Emma simply forgot to switch it off before she retired for the night. Her flatmate is usually prompt in rising, so when she hasn't appeared by the time Sybil emerges from the shower, the first note of concern is raised. Sybil tentatively knocks on her door and calls her name, softly at first and then in a firmer tone. On receiving no reply, she hesitantly opens the door, wondering if she might be disturbing an unexpected romantic tryst. However, the sun is streaming through Emma's open curtains and her bed is made; her dressing gown lying across the duvet where Sybil had seen her throw it from the doorway yesterday morning. Sybil is instinctively uneasy; Emma usually lets her know if she's going to be away overnight and she checks her phone to see if she has missed a text. With nothing pending, she logs quickly into her email but there has been no nocturnal activity and she frowns as she considers the implications. She's more responsible since she finished her foundation training and found a full time job. However, there were certainly times in the past when she's drunk more than intended and crashed at somebody's house rather than stagger home worse for wear and she doesn't begrudge Emma the opportunity. Her flatmate is eighteen months younger and nobody's life is in the balance if she's under par at work today.

She intends to send her a text for self-reassurance, but she hasn't allowed sufficient time once again and ends up running to the tube station in an attempt to make up for the longer journey to Guy's. As she munches on a shop bought sandwich at lunchtime, she remembers and fires off a quick message.

Everything OK? R U home tonight?

She checks her phone when the unit closes at 4pm, prior to finishing her paperwork, but there's been no response, so she rings her and leaves a message. When she leaves for home an hour later, there's still no reply, so she calls Emma's work number and frowns when it goes straight to voicemail. However, it's only as she arrives home and presses the flashing light on the answer machine that her nagging sensation of unease reaches another level.

"Hi Emma, this is Nicole from work. Just checking that you're alright. Can you give us a call back?"

Sybil presses 1471 but the number is withheld. She tries Emma's direct line again and is unsurprised by her lack of success. With relief she remembers that the office is open until 6pm and if she's swift, she might just catch a receptionist on the switchboard. She has no idea what Nicole's surname is, but mentions the department name and the call is quickly diverted.

"Hi, this is Emma's flatmate. I just got your message at home and was a bit concerned. Has Emma not been in today?"

"No, nor yesterday" replies Nicole and Sybil feels the soft ghost of a chill sweep cross her body, giving an involuntary shiver as she hears the enquiry. "Is she ill?"

"Um…I'm not sure…look, I'm sure there's a perfectly good explanation for this, so I'll make a couple of calls. Er…so she didn't go to your drinks event last night then?"

There is a pause. "What drinks event?" Nicole asks.

Sybil paces the flat, chewing a nail with indecision and feeling a growing knot of anxiety in her stomach as she tries to objectively consider what might have taken place. There has to be a reason behind Emma's absence, it's just a matter of figuring out a possible solution so that she can relax. Nothing wholly dreadful has ever happened in her life and she's sure that this is going to be a simple case of misunderstanding. By 8pm and having left two further messages on Emma's mobile, she wonders if there's been a family emergency and whether she's gone home to Dublin on impulse. She has no contact details for her mother; knows only the sketchy details of a deceased father, step-father she doesn't care for and a petulant teenage half-sister. She could try to trace the family home, although it's a common enough surname and she doesn't even know the Dublin suburb where she was raised. There are two brothers in England however; one up in Liverpool and the other in North London. The latter had helped her bring boxes up into the flat on the day she'd moved in. She remembers a sullen, dishevelled looking man who had seemed resentful at the intrusion to his day and who disappeared into their communal garden for a cigarette every half hour or so. He hasn't returned subsequently, but Emma often visits him at weekends and stays over. Surely he would know if there's a crisis back home, although it's possible that they've travelled back together. He's a journalist; the London correspondent for either the Irish Times or Irish Herald, she can't remember which and reads neither. But Emma looks at his articles online and claims that he's wildly talented.

Sybil walks into Emma's bedroom and looks around for any sign of an address book or diary. It appears that she took her laptop into work yesterday, so there's no other way of easily retrieving contact details. Hesitantly and feeling a displaced sensation of guilt, she opens drawers and glances inside, reluctant to start rummaging around for she feels sure that phone numbers would not be hidden away under underwear and t-shirts. There's one drawer which contains miscellaneous paperwork, but she finds only credit card receipts, bank statements and a manufacturer's guarantee for her hairdryer.

She returns to her own bedroom, lifts her iPad from the bedside cabinet and sits down, flipping open the cover and pausing momentarily before she types into the search engine.

'Tom Branson journalist'

Numerous links appear and she clicks on one, a report on the incarceration of an Irish national for fraud last year and scrolls through it urgently. Concluding the article is an email address, tbranson at irishherald shows that it would reach him directly, but she doesn't feel that this is the type of enquiry that he ought to receive in writing. She looks up a telephone number for the newspaper, is unsurprised to learn that its switchboard closes at 5.30 but at the end of the automated message, there's an out of hours number, a plea for urgent enquiries only. It rings for some time and she expects to leave a message, but a gruff male voice answers and she politely explains her predicament.

"I'm a friend of his sister and there's a bit of a problem…" she explains "I really need to reach him." She has no knowledge of whether the British Data Protection Act has its origin in Brussels or Westminster, but she expects to have to leave her own number as a precaution, so is startled when the voice returns and offers her a mobile number before abruptly hanging up.

She takes a deep breath, anxious about the potential worry she may be about to cause, but hoping he will provide resolution to her search, then punches the number into the keyboard of her phone. He answers on the second ring.