This is the movie version of the song from Scott Pilgrim vs The World sung by actor Brie Larson and performed by the fictional band The Clash at Deamonhead. The original song was created by Metric who are featured on the movie soundtrack.
The song was originally made in 2007 and was posted to Myspace with the title Freddie after Freddie Mercury.
The song is about a couple who have broken up after having a strong connection to each other and now they refer to each other as just friends “Friend of a Friend”.
Their common goal was to stay together until death but something happened between them.
The female in the relationship sends her “love on a wire” meaning she sends her love from a distance on an old form of communication of telegraphy which is a piece of equipment used to send Morse code.