Silhouetted against the abyssal gloom of the deep Atlantic Ocean by spotlights and garish advertising lined with flickering neon trim, she swam freely. Her lithe, waifish body, with lanky adolescent proportions, belied unnatural strength able to resist the steel-crushing pressure of the depth. Encased within a leathery form-fitting diving suit armored by metal bracing, her only view out of the orb-shaped helmet a singular cyclopean porthole through which a crimson glow emanated, she surveyed the crumbling edifices of the city on the seabed.

Rapture, with its glass-domed Art Deco seascrapers, the only home she had never known, was a decaying monument to the hubris of a man who lay years dead. As a young girl, mental conditioning had allowed her to wander the drowned metropolis while seeing it as a phantastic playground. With childhood's end, the glimmer wore off and facing the nightmarish reality became unavoidable.

ADAM, the genetic wonderdrug which put the impossible within the grasp of anyone through whose veins it flowed, was the engine that drove Rapture. She was intrinsically linked with the substance by its source, the sea slug implanted into her body in order to enhance production. The horror of her role as a Little Sister, the girls from whose bodies ADAM was extracted and through which it was recycled by draining and drinking the blood of the city's many corpses, as well as the immense direct doses of the drug and the cacophony of dissonant voices inside her mind — echoes of genetic memory shared by ADAM — all compounded to fray her fragile sanity. The frightened girl with a forgotten name had grown into a Big Sister: the last line of defense for the current crop of Little Sisters, mostly comprised of abductees from the surface, as they wandered the dilapidated promenades, flooded apartments, and abandoned shopping arcades in search of 'angels.'

A piercing psionic cry for help shattered her contemplative moment. Hypnotic compulsion made the distress signal impossible to ignore. The Big Sister cut through the water with purposeful strokes, guided by telepathic bond to the appropriate airlock. Dripping with seawater, she skittered, spider-like, along the concrete ceilings and arched spans of glass, until arriving at last.

The barefoot girl clung pitiably to the inert hulk of a diving suit that lay slumped in a heap, surrounded by mauled remains. The Bouncer had not fallen lightly, its drill bit covered in a sheen of fresh gore. A mournful tinge crept into the Big Sister at the loss of 'Mister Bubbles,' each of the ones who had protected her as a child indistinguishable in the fog of memory. He would be avenged.

A semi-circle of Splicers — 'Damned Sploicers,' a ghostly thought intruded in a foreign lilt — closed in like hyenas. The Big Sister leaped into the fray, emitting a paralyzing shriek. At once, she clutched the nearest Splicer's neck, hoisted him off his feet, and impaled the oversized needle that ran along her arm into his gut, experiencing a surge of power as the ADAM drained directly into her bloodstream