Steins;Gate - episode 19 - 09 Aug, 2011

As Kurisu offers to look after Mayuri at a doujin convention, Okabe heads to Moeka's apartment, only to learn that she committed suicide. Okabe leaps to time before Moeka killed herself, finding her a nervous wreck due to not having been contacted by a person she calls "FB," who had given her the orders to find the IBN. Okabe steals Moeka's phone and sends a D-Mail from it, but the timeline does not shift, leading him to realize that she had lied about the contents of the message she had sent in the previous world line. He then confronts Moeka about FB and tells her about her future suicide. Okabe finds the offending text, which involved the location of the IBN 5100, but annuling it via another D-Mail still does not change the world line. As Okabe decides he needs to send a D-Mail from FB's phone, Moeka, feeling betrayed, tells him the location of the IBN 5100. (Source: Wikipedia)