"There Are Lines", alternatively "Don't Cross That Line", is a song in Death Note: The Musical.
After L's broadcast in which he used Lind L. Tailor, Soichiro Yagami visits his son Light. They discuss L, the investigation, and what happened. Soichiro condemns the sacrifice of Tailor's life with this song, saying that L crossed a line. Light joins in, saying that he understands and he follows his father's example.
The song was originally written in English, but an English-language version has not been released. The original English title of the song is "There Are Lines".