Dateline NBC (8pm, NBC) - A special two-hour "Dateline" revisits the death of Durham's Kathleen Peterson and the conviction of her husband Michael Peterson for her murder, with fresh interviews and recent developments in the case. Here's a preview of the episode.
Inside World War II (8pm, NGC) - A documentary sharing firsthand accounts of World War II through archival footage and more than 50 testimonies from American, British, German and Soviet service members.
Treehouse Masters (10pm, Animal Planet) - In this new eight-episode series, world-renowned treehouse designer and builder Pete Nelson (left) travels the country with a team of skilled craftsmen to build super high-end treehouses for their clients. Nelson uses science and art to create homes and businesses that are sustained by the trees. Nelson and his crew construct homes in New York, Texas, Ohio and Seattle. If you're into treehouses, also check out "Ultimate Treehouses" on Animal Planet at 8.
Merlin (10pm, Syfy) - In the series finale, Merlin faces his greatest challenge as Morgana threatens to destroy King Arthur and Camelot.
Mystery Diners (10pm, Food) - The owner of a Texas restaurant chain called Cooper's Old Time Pit Bar-B-Que suspects that one of his employees has divulged a secret family recipe to a rival business.
Wild West Alaska (10pm, Discovery) - Ken and Phred promote the store with a contest for mustaches and beards. Also, Jim builds a custom rifle for a river guide, but the plane delivery is problematic.