CHUCK

NBC, 8 p.m. ET

SERIES FINALE: At the cliffhanger teaser for the end of last week’s episode, Sarah (Yvonne Strahovski), brainwashed by villains with all memory of her time with Chuck (Zachary Levi) erased, was given orders for her latest “mission” – to kill Chuck. But however this series will end tonight, that won’t be the way. Pictures released in advance show the heroes reunited, ready to take on the bad guys for one last stand. The real villains on this series, though, were the scriptwriters, who went downhill quickly after the first season.

FRINGE

Fox, 9 p.m. ET

More cliffhangers, and more confusion – this time having to do with yet another possible universe, as well as that troubling prediction that has Olivia (Anna Torv) – one of the Olivias, anyway – worried about her future. As in: worried that she won’t have one.

GREAT PERFORMANCES: “TONY BENNETT: DUETS II”

PBS, 9 p.m. ET (Check local listings)

When making his Duets II CD, Tony Bennett set up cameras during the recording sessions, and tonight’s special presents the visual, as well as aural, fruits of that labor. One clear highlight, seen already during Lady Gaga’s Christmas special for NBC, is her duet with Bennett – but another highlight, a more poignant one, is “Body and Soul,” as sung by Tony Bennett and Amy Winehouse at England’s Abbey Road studios.

SPARTACUS: VENGEANCE

Starz, 10 p.m. ET

SEASON PREMIERE: This may as well be a series premiere as well, since the death of Andy Whitfield, who played Spartacus last season, has resulted in the character being recast. Now it’s Liam McIntyre who leads the slave revolt – and, as Spartacus, encounters a character who, last season, was presumed (and left for) dead: Lucy Lawless’ Lucretia. She resurfaces, but mentally even more than physically, appears much the worse for wear.

MERLIN

Syfy, 10 p.m. ET

Here’s a coincidence to warp the minds of genre fans. Last season’s Game of Thrones ended with the hatching of dinosaur eggs. Well, tonight on this medieval drama series, the plot involves… the last surviving dragon egg. And if Merlin (Colin Morgan) isn’t careful, the yolk’s on him.