1) “The Show Must Go On,” 8-10 p.m., ABC. “American Idol” has vacated Mondays; now it’s Sundays-only. And tonight, its spot goes to one of its most famous losers: Nine years ago, Adam Lambert finished second to Kris Allen. He’s one of many – Katharine McPhee (2nd), Chris Daughtry (4th), Jennifer Hudson (7th) – who surpassed the winners. In 2014, Lambert started touring with Queen; they’ve drawn big crowds and even opened the Oscars telecast. This documentary traces their stories.
2) “American Spring Live,” 8 p.m., PBS. Let’s credit this with scope and ambition. For three nights, PBS will look at nature in the springtime. Mixing taped features alongside the live coverage, it will range from the Everglades to the Sierra Nevada Mountains.
3) “The Big Bang Theory,” 8 p.m., CBS. Now that “The Neighborhood” has ended its season, CBS imports a “Big Bang” rerun. It’s a pretty good one, catching the time when Sheldon and Amy thought their theory had been disproven. That provides a boost for “Man With a Plan” (8:30 p.m.), which is still teetering between renewal and cancellation, with two new episodes left.
4) “9-1-1,” 9 p.m., Fox. In other shows, Peter Krause and Angela Bassett have tangled with the subtleties of the human psyche; in this one … well, they’re often underemployed. Tonight, however, the show backs up to tell the story of Bobby (Krause). After a family tragedy in Minnesota, we see him move to Los Angeles, where he becomes captain of the rescue unit and meets Athena (Bassett), a cop.
5) “Ms. Fisher’s Modern Murder Mysteries,” any time, www.acorn.tv. For three seasons, “Miss Fisher’s Murder Mysteries” followed a glamorous detective in 1920s Melbourne. Now we jump to the 1960s. Perregrine Fisher is bright, beautiful and drifting, a failure at everything except romance. Hen she inherits everything – mansion, money, friends – from the crimesolving aunt she never knew. There are four movies here; the first is a bit daft at times, but uses its ’60s mod setting to remain bright and fun.