CSI began this week with a tease: Jorja Fox’s Sara Sidle at a benefit for a foundation for the deaf, received a call from her hubby, William Petersen’s Gil Grissom. Ah, how nice it was to hear Grissom’s familiar rasp, even distorted through a smartphone. “I’m still in Peru,” he said — he’d miss the function, which was attended by his mother (Phyllis Frelich), a guest star (Marlee Matlin), and … surprise!: a death. By the end of the hour, we were granted a glimpse of the much-missed Gil.

Matlin, playing a testy academic, was briefly a suspect in the murder case, before the investigation’s net was cast wider. The tale was complicated by, as Matlin’s Julia Holden signed to Sara, “my history with your husband. We were involved, intimately.” Smug and aggressive, Holden was actually the woman Grissom’s mother preferred to Sara; Betty Grissom had bonded with Holden in a way she never has with Sara. “Julia has been like a daughter to me,” she said. (Makes sense — I mean, how long have Gil and Sara been married-but-separated-by-vast-distances?)

CSI has lost its mojo since Petersen’s Grissom left; enough time has passed to say flat out that Laurence Fishburne’s Ray Langston just hasn’t been as interesting a character. Langston is less a strong leader — or, as in the case of Grissom, a fascinatingly eccentric one — than just another member of the team, which has pushed Marg Helgenberger and George Eads to the fore. They’re fine, to be sure, but their characters always seem to be waiting for Gil to poke his head around a lab corner to give an inscrutable order or test them on an arcane theory.

This episode had a teleplay by coexecutive producers Treena Hancock and Melissa R. Byer, good writers who authored one of this season’s better episodes, November’s “Wild Life.” Hancock and Byer are adept at sketching fully formed female characters, whether it’s Gil’s firm, intelligent mother (Frelich embodied her perfectly) or creating the gal-pal dialogue between Sara and Helgenberger’s Catherine.

Nevertheless, this episode, titled “The Two Mrs. Grissoms” — a humorous reference to Gil’s mom and Sara — despite the explosion of two bombs, didn’t have much to spark it, not even with Matlin cranking her flintiness to full flare.

To be honest, the whole thing left me thinking, during the commercials, of CSI‘s glory days, with Gil parrying quips and whips with Lady Heather.

“What kind of marriage do you have?” Mrs. Grissom asked Sara. “We talk every day,” Sara protested. “What Gil and I have works.” Too bad CSI doesn’t, very often, these days.

At the very end, the case solved and already forgotten, we saw Sara talking to Gil via laptop camera. It was great to see Petersen again, bearded, happy, and chattering about Incan culture. Gil’s mom soon joined Sara. Gil said, “When I come back, the three of us will go out to dinner, soon.”

Can’t come soon enough, Gil.

Did you watch? What did you think?

Twitter: @kentucker