Given the task definition and input, reply with output. In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.

Chuck Bartowski: The mission 's over dad .
Steve Bartowski: It 's never over , all right ? There 's always another _ one _ and another . And ... the reason a spy has to have one of those is because every mission they go on could be their last . For every spy , there 's someone who cares about them . Someone who has to open that box , read that message , and mourn their loss . This is a bad business . And I do n't want my family any part of it !
mission