The Doctor loves to make Amy wait, doesn’t he? It’s almost pathological as if he thinks she has some sort of issue with patience.  And he takes it to ridiculous new heights in the latest outing for the series, “The Girl Who Waited”, written by Tom MacRae, who had previously contributed the season two episodes “Rise of the Cybermen” and “The Age of Steel”.

Not that it is on purpose. The episode starts off innocently enough; the Doctor wants to take Amy and Rory on vacation, and instead winds up in a white hallway with a door and two buttons. Unbeknownst to them, each button leads to the same room but in a different time stream; the Doctor and Rory wind up in one, and Amy in another. Complicating things is that the white rooms are a quarantine area for a disease that would prove fatal to the Doctor. As such, with glasses made from technobabble, Rory ventures out to find Amy, and does- but she has already been alone for 36 years.

What follows is an emotionally powerful piece where Karen Gillan, in dual roles as young and older Amy, clearly steals the show. Tom MacRae’s script provides enough rich material for Gillan to work with, crafting a believable and beautifully nuanced version of an older, bitter Amy. She nails everything- the change in cadence of her voice, the different walk, and hardened heart and attitude, especially towards the Doctor. It’s impressive that Gillan did not simply rely on the prosthetic makeup but really stretched herself as an actor, and it paid off wonderfully. It’s tough to watch as she coolly responds to Rory at first; but the episode tugs on your heartstrings as it moves along, until the painful climax. Without wanting to give too much away, that scene near the end, with the older Amy and Rory speaking at the TARDIS door, is a punch to the gut. Clearly the most emotional scene in the series in a long time, if ever, it also provides some of Arthur Darvill’s best acting.

The episode itself plays with some interesting ideas; overlapping time streams, a unique way to deal with a terminal illness, the sterile white scenery contrasted against the morbid intent of the quarantine center- it all works, providing that sense of sci-fi wonder that Who has been so good at, particularly under lead writer Steven Moffat’s reign. It is also refreshing that the episode stuck with making some hard choices, and opted not to take an easy and sappy ending.

“The Girl Who Waited” is a solid contribution to the series. In a lesser actress’ hands, the dual role could have been a mediocre contrivance. But Gillan nails the part, and makes us care about what the older version of Amy has been through, and get hit hard at the end. It also works as a standalone episode, without any reference to the ongoing season six arc, so new viewers can jump onboard with minimal fuss. This is easily a great episode to introduce them to Doctor Who.