Screenplay Structure Analysis

Lights Out

Written by Eric Heisserer · Horror · 107 pages · 110 scenes · 3-act natural structure · linear organization · Analysis confidence: High

A young woman must confront a supernatural entity from her mother's past that can only exist in darkness, threatening her family when the lights go out.

Tone
Tense, claustrophobic, emotionally grounded supernatural horror with familial trauma undertones

Tension curve

Dramatic intensity across Lights Out from first page to last, sampled at 40 points on a 0–10 scale. Values: 4.3, 4.8, 5.3, 5, 5.3, 5.3, 6, 5.8, 6.3, 6.5, 6.7, 6.7, 7.2, 7.7, 7.5, 6.3, 5.4, 5, 5.1, 5, 5.2, 5.8, 6.3, 5.9, 5.4, 5.8, 6.7, 7.8, 8, 8.1, 7.9, 7.9, 8.1, 8.3, 8.3, 7.6, 7.1, 7.6, 8.8, 9.6.

Structure at a glance

Inciting incident
Page 18, 17% of the script: Rebecca arrives at the school with Bret; Emma from Child Services introduces herself, explains she was assigned to Martin after Paul's death, and asks about Martin's sleep and home situation while Rebecca clarifies Paul was her stepfather.
Act 1 break
Page 27, 25% of the script: Rebecca commits to investigating Diana after discovering the name carved in her floor and receiving Paul's voicemail about his death.
Midpoint
Page 49, 46% of the script: Rebecca reveals to Bret that her mother was a patient at the hospital and had an imaginary friend named Diana; Bret discovers boxes of micro-cassette therapy session recordings.
Act 2 break
Page 72, 67% of the script: The family is trapped in the basement with Diana hunting them, forcing Rebecca to confront the entity directly rather than continue running.
Climax
Page 93, 87% of the script: Officer Gomez hears her partner scream and calls for backup; Rebecca offers her the black light but Gomez moves toward the back room; a silhouette appears and Rebecca grabs Martin to flee.
Peak tension
9.6 out of 10, reached about 100% of the way through; the script averages 6.6.
Average scene length
1.3 pages

Structural personality

This script operates as a tightly-wound escalation machine. Act One establishes the threat through Paul's death and Martin's terror, pulling estranged Rebecca back into her mother's orbit. The structure cleverly uses two households—Sophie's and Rebecca's—as parallel hunting grounds, allowing Diana to pursue the family across locations. Act Two is investigative horror: Rebecca uncovers Diana's origin through medical tapes and storage unit discoveries, while Diana's attacks intensify. The basement trap at scene 80 marks the point of no return—no more running, no more denial. Act Three becomes a siege, with the family weaponizing light sources in increasingly desperate ways until Sophie's final sacrifice. The script's architecture mirrors its theme: you can't outrun your mother's darkness; you can only face it or let it consume you.

Pacing

The opening 20 pages move with relentless efficiency—Paul's death (scenes 1-4), Rebecca's introduction (scenes 5-11), Martin's school crisis (scenes 18-22)—establishing all major players and the threat before page 23. The middle section (scenes 48-60) slows for investigation and character work, building dread through research rather than attacks. The final 30 pages (scenes 80-110) are pure survival horror with almost no breathing room, using the basement siege and then Rebecca's apartment invasion as back-to-back pressure-cooker sequences. Scene length averages 1.3 pages, but the script uses rapid-fire scene cuts in moments of peak tension (scenes 91-99 cover the police arrival and Sophie's death in just 7 pages) while allowing longer scenes for emotional beats like the dining room confrontation (scene 68) and basement revelations (scenes 82-91).

Themes

Similar shapes

Screenplays whose tension curve most closely matches Lights Out.

Scene summaries and structural markers are generated by AI analysis of the screenplay text and may contain minor inaccuracies. ScriptGraph analyzes structure and does not reproduce screenplay text.

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