The opening montage: a story of the Kims' happy family life where it follows the activities of each family member through their accounts on their shared Windows XP computer. Both David and Pamela take pictures and videos of each moment of Margot's lives and treasure them in their computer, up until Pam becomes sick and eventually dies with Margot tearfully playing a song next to her. The whole sequence is comparable to Pixar's Up's opening montage of Carl and Ellie's lives.
The ending. After going through hell for a whole week, David finally found his daughter, who's heavily injured but still alive. In the epilogue, it's revealed that the whole experience led to the two reconciling during Margot's stay in the hospital, and she finally returns to playing piano and is very much looking forward to applying to a music academy, with David supporting her all the way and finally affirming to her that her mother would've been proud of her.
Special mention goes to Margot replacing her desktop background. While a small act, replacing the picture of her mom with a picture of her father proves that she's ready to move on and heal from her grief.
Peter is in the middle of reaming out his brother for suspecting him of harming Margot when the call comes in that a suspect has been apprehended and has confessed to her murder. David collapses to the floor sobbing in grief, at which point Peter immediately forgets the argument and rushes to help him.
