What’s Worth Watching: ‘The Big Bang Theory’, ‘Legends of Tomorrow’, ‘The Blacklist’ and more for Thursday, April 28

The Big Bang Theory (8/7c, CBS): While the rest of the gang goes to a wine bar, pregnant Bernadette (Melissa Rauch) gets some alone time with Sheldon (Jim Sheldon)—which seems unfair, because if anything calls for a drink … Still, the imbibers face their own complications, when Penny runs into her former beau, Zack (Brian Thomas Smith), and Raj (Kunal Nayyar) doesn’t get the reception he expects upon introducing his latest girlfriend, Claire (Alessandra Torresani).

DC’s Legends of Tomorrow (8/7c, The CW): Rip (Arthur Darvill) brings his fellow time-travelers back to his future, to 2166 London, shortly before his own family is wiped out, in a last-ditch effort to defeat Savage (Casper Crump). Could Savage’s own daughter (Jessica Sipos) be the key to victory?

The Blacklist (9/8c, NBC): The mysteries deepen in the wake of the task force’s recent loss, as they face an enemy using a worldwide satellite network, while Red (James Spader) faces a “ghost from his past,” who knows his secrets. Please, please, let this ghost spill a few of them.

 Inside Thursday TV: More relationships are put to the test on ABC’s incredibly durable Grey’s Anatomy (8/7c) as Meredith (Ellen Pompeo) urges Amelia (Caterina Scorsone) and Owen (Kevin McKidd) to commit once and for all. And the custody situation between Arizona (Jessica Capshaw) and Callie (Sara Ramirez) gets complicated, putting their friends in an awkward bind. … It’s a raucous Community mash-up on Spike’s Lip Sync Battle (10/9c) when Joel McHale goes up against the rarely restrained Jim Rash (better remembered as Dean Pelton). … Jessie (Bre Blair) may be putting herself in harm’s way on NBC’s twisty Game of Silence (10/9c) when she goes undercover by volunteering at the political campaign of loathsome former warden Ray Carroll (Conor O’Farrell). Beware the belly of this beast.