Answer (direct): The moment a well-chosen, iconic song starts playing in a film to immediately establish mood, theme, or character is often called a needle drop or a music cue that “sets the scene.” It’s the point where the song and image align to signal tone, era, or turning point, making the musical moment inseparable from the scene in the audience’s memory. Context and examples

• Needle drop: A specific, memorable song begins or reprises at a pivotal moment, crystallizing the scene’s meaning and leaving a lasting impression. Classic examples include “Don’t You (Forget About Me)” in The Breakfast Club and “Where Is My Mind” in Fight Club. These moments are widely cited as defining musical moments that frame the film’s emotional arc.
• Scene-setting songs: In many films, a recognizable track is used at opening credits, transition moments, or climactic sequences to anchor the viewer's perception of the scene’s mood, era, or stakes. The association between the track and the visuals becomes a shared memory for audiences.

Notes for your search or puzzle

• If you’re solving a crossword or trivia clue about “the point in a film when an iconic song sets the scene,” the answer often hinges on a term like needle drop or a specific, widely-recognized cue.
• Popular culture lists and crosswords frequently highlight famous needle drops as quintessential moments where music defines a scene.

If you’d like, share the exact film or song you’re thinking of, and I can describe how that musical moment functions to set the scene in that particular movie.