Dirk Gently’s Holistic Detective Agency 9 p.m., BBC America

In the series premiere, eccentric detective Dirk Gently (Samuel Barnett) joins up with reluctant sidekick Todd (Elijah Wood, right with Barnett) for some unconventional crime-solving. The show is based on the novels by Douglas Adams.

Weiner 9 p.m., Showtime

This documentary profile follows former congressman Anthony Weiner as he runs for mayor of New York City in 2013. Whoops, here comes another widely publicized sexting scandal! Political career: derailed.

Death of a Vegas Showgirl 8 p.m., Lifetime

A sordid love story.

Downtown Shabby 9 p.m., FYI

Farmhouse kitchen modernized.

Oprah: Where Are They Now? 10 p.m., OWN

Former teen star Aaron Carter.

Matthew Gilbert can be reached at gilbert@globe.com. Follow him on Twitter @MatthewGilbert.