What to Watch on Friday: Heroes unite for ‘Marvel’s The Defenders’ on Netflix

Marvel’s The Defenders (Netflix) – This series follows four super heroes with their own personal challenges – Daredevil (Charlie Cox), Jessica Jones (Krysten Ritter), Luke Cage (Mike Colter) and Iron Fist (Finn Jones) – on a mission to save New York City.

Treehouse Masters (9 p.m., Animal Planet) – Pete goes to western Washington state to make a tree house with a 55-foot-long bouncy bridge entryway and a zip line that travels through the forest.

Wynonna Earp (10 p.m., Syfy) – Allies become enemies when a vengeful wish goes awry.

Lion Kingdom (10 p.m., Nat Geo Wild) – A male lion’s reign gets tested when a younger rival fails to follow the rules of the pride.