One of four endings to Bioshock 2. Sofia Lamb's bombs detonate and cause a section of Rapture to plummet towards a trench. This wounds Subject Delta mortally but he manages to cling to the escape pod. Eleanor saves her mother by giving her an oxygen mask and extracts ADAM from you to absorb your consciousness (memories, conscience etc.) before you die.
The scene ends with her discarding a Subject Delta doll when surrounded by the rescued Little Sisters, symbolizing a new beginning just as she says. The shining sun also relates back to her expression of not being afraid to see the surface. This was a happy / sad scene made all that much better by the music.
To obtain this ending you should save every Little Sister. Sofia Lamb's fate in this ending only depends on saving at least one life, if you kill everyone then she will die.
The music which plays during this scene is Eleanor's Lullaby: