The majority of the episodes this season, with the exception of “Echoes” and “A Man Of His Word”, have been stand-alone. That is, un-connected in terms of a running plot. There have been a few hints dropped towards some greater story at play, mostly in terms of Jack (Victor Garber) and Sloane’s (Ron Rifkin) secret pact. But that was it.

“The Index” however is the first real instalment that pushes at the larger story. In a nutshell, Dixon (Carl Lumbly) asks Sydney (Jennifer Garner) for her help as he believes Sloane is subverting the CIA and attempting to reform the Alliance which was destroyed four years earlier. But in order to do that, Sydney must go up against her own sister whom she is prophesised to fight to the death.

In the preceding episodes, particularly “Détente” and “Echoes”, there has been a definite emphasis on Sydney and Nadia’s (Mia Maestro) relationship. They work well as a team and give the series a very smart, sexy and action packed angle to work with. So after only a few episodes building up this dynamic, throwing a wrench into the works was a bit of an unexpected turn. Well, maybe not completely unexpected. This is Alias after all. Everyone knew the wrench was coming, it was just a matter of where and when. It looked like it was going to be later, perhaps as Nadia uncovers Jack’s involvement in Irina’s death.

But it happened now.

Syd not only violated Nadia’s trust, but also used her as an excuse to enter Sloane’s home and tap his phone. The operation itself felt very much like one we have already seen back in the first season. Jack, Syd, Sloane and his wife Emily (Amy Irvine) are enjoying a nice intimate dinner in order for Sydney to access the Rambaldi pages in Sloane’s study. Even Syd’s escape from dinner was the same – a phone call from an upset friend. But no matter, in that mission Syd had Jack watching her back. Here, she is utterly alone. The suspense was kept at a high, and Mia Maestro done a note-worthy job during her highly emotional argument with Sydney afterwards.

With the exception of Marshall (Kevin Weisman), all of the other characters seemed to get their own little piece of the action – Dixon’s investigation of Sloane, Vaughn’s (Michael Vartan) discovery that his father didn’t die in 1979 as he believed and Weiss’ comical escapades in France (as well as the awkward silence at dinner with Sloane).

Angela Bassett gave another excellent performance as CIA Director Chase. As with “Authorised Personnel Only”, it was good to see some kind of an authority figure. All of the characters seem to get away with so much rogue behaviour without any real consequences, so the inclusion of the Chase character goes a long way to solving that problem. In just three episodes, Bassett has made the character her own, carving out her own little home on Alias. A home she will always be welcome to return to. There may even have been a few sparks flying between Chase and Dixon, something which could complicate things in the future – we all know how the Alias team enjoy complicating issues.

But the highlight of the episode wasn’t the as usual stunning performance from any of the cast, nor the high paced missions. It was simply what wasn’t revealed. In several occasions, it has been proven that questions are far more entertaining to watch than the answers. The X-Files lived by this rule, and Alias seems to be following suit. We know Jack and Sloane have a master plan, we now know Vaughn’s father wasn’t killed in 1979…and someone wants him to find out. The shows mysteries and agenda’s are all moving in so many directions that like the wrench, its only a matter of time before they all collide...and thats when it all hits the fan in true Alias style.