The official synopsis of "One Door Closes" -- "Agents of S.H.I.E.L.D.'s" March 31st episode -- holds some surprises, up to and including Edward James Olmos first appearance and Lucy Lawless's return to the show.

When we last saw Lawless' character Isabelle Hartley, she had apparently died in a car crash. However, according to this synopsis, Hartley is slated to return; in what capacity, however, is left for us to guess.

"I knew she was dying before I went into it," said Lawless in an interview with The Hollywood Reporter this past January. "It was kind of out of respect for [producers] Maurissa [Tancharoen] and Jed [Whedon], but if she comes back it would be because there happened to be a hole in my schedule and that it was a good through line for it. Unless they're going to bump somebody off, they're not bringing back Izzy Hartley in a way that is substantive."

Check out the full synopsis below.

"One Door Closes" - War comes to Coulson's doorstep in a way he never anticipated as shocking revelations are brought to light, and Skye struggles to control her new abilities but will soon make a decision that irrevocably changes her life, on "Marvel's Agents of S.H.I.E.L.D.," Tuesday, March 31 (9:00-10:00 PM, ET) on the ABC Television Network.

"Marvel's Agents of S.H.I.E.L.D." stars Clark Gregg as Director Phil Coulson, Ming-Na Wen as Agent Melinda May, Brett Dalton as Grant Ward, Chloe Bennet as Agent Skye, Iain De Caestecker as Agent Leo Fitz, Elizabeth Henstridge as Agent Jemma Simmons, Nick Blood as Lance Hunter and Adrianne Palicki as Bobbi Morse.

Guest starring are Henry Simmons as Alphonso "Mack" Mackenzie, Lucy Lawless as Isabelle Hartley, Edward James Olmos as Robert Gonzales, Jamie Harris as Gordon, Christine Adams as Agent Weaver, Kirk Acevedo as Agent Calderon, Cornelius Smith, Jr. as Case, Sai Rao as Susanna, Mackenzie Astin as Tim Maguire and Rick Otto as lead Hydra agent.

"One Door Closes" was written by Lauren LeFranc & Rafe Judkins and directed by David Solomon.

"Agents of S.H.I.E.L.D." airs on Tuesday at 9 p.m. EST on ABC.