Sleepy Hollow The supernatural drama encores its fourth-season premiere; with Tom Mison. 8 p.m. Fox
The Guardians This new docu-series follows an all-volunteer group of animal-welfare advocates who go above and beyond to protect all creatures great and small. 10 p.m. Animal Planet
iHeartRadio Music Festival — Night Two Usher, Sting, Britney Spears, Ariana Grande and Florida Georgia Line are among the performers taking the stage in Las Vegas in this encore special hosted by Ryan Seacrest. 8 p.m. KTLA
Hachi: A Dog’s Tale Richard...