Pretty Little Liars
This seven-season teen mystery thriller follows four high-school girls being stalked and blackmailed by an anonymous figure who threatens to expose their secrets, across a backdrop of murder, adult-teen relationships, and sustained psychological menace. This report covers the full series run (Seasons 1–7, 2010–2017).
Mature teens aged 14 and up, ideally watched alongside a parent who can discuss the many adult themes.
Episodes to know about
The pilot establishes the core threat immediately: a dead teenage girl's body is discovered and the four leads begin receiving anonymous threatening messages signed 'A' -- this stalking premise drives every episode that follows.
A teenage girl meets and kisses an adult man at a bar, then discovers he is her new high-school English teacher; the romantic relationship between them continues and is treated as a love story rather than a safeguarding concern.
A flashback reveals how a classmate was accidentally blinded in a traumatic incident involving the main characters -- this backstory resurfaces with tension throughout the early seasons.