It's Over is a short song sung by Big Time Rush in episode "Big Time Single". It's a short, musical part of episode, when sobbing James and Carlos joined Kendall and Logan to record the song, while they were heartbroken.
Logan: She's gone forever
Carlos: (While sobbing.) I'll never forget her face (Starts crying.)
James: She says it's over... (Sobs.)
Kendall: She moved so far away
James and Carlos: It's over, it's over! (Crying.)