Catalyst: Don’t Die Young, 8pm, ABC The first of a six- part BBC series about our vital organs focuses on the kidneys. Meet Alice Roberts, an anatomist who can’t wait to start cutting up kidneys to show us how they work. What can we do to look after our vital organs? Fast paced and funky, this show will teach you what your kidneys are for and how to maintain them in first- class working order. Law & Order: Criminal Intent, 9.30pm, Ten Fulla T, a rapper who encourages his fans to report crimes when they see them ( right!), is murdered outside a radio station. ‘‘ It’s not about bein’ a snitch,’’ he raps, ‘‘ it’s about doin’ what’s good, and livin’ right.’’ Talk about famous last words. Logan ( Chris Noth, pictured) and Wheeler ( Julianne Nicholson) are forced to work with a detective from the gang unit. When key witnesses start dying, they begin to wonder what side of the law their new mate is on. The Kidnapping of Elizabeth Smart, 9.35pm, ABC A million miles from the slick predictability of Dick Wolf’s Law & Order franchise, this is the true story of the kidnapping of Elizabeth Smart, a 14- year- old who was abducted at knifepoint from her bedroom in her Salt Lake City home in 2002. Emotional family members recount the incident and the long, painstaking struggle to keep the investigation alive. Nine months later, Elizabeth was discovered, veiled in white and walking with her captors on the outskirts of the city.