The episode follows Sherlock Holmes (Benedict Cumberbatch) and John Watson (Martin Freeman) as they race to solve a series of seemingly unrelated cases presented by a mysterious bomber.
After four such cases, the episode ends in a standoff between Holmes and the bomber, who it turns out is Jim Moriarty, the "consulting criminal" and the main antagonist for the rest of the series.
Critical reception of "The Great Game" was highly positive, being praised for its complex and gripping plot, and its unusual and original portrayal of Moriarty.
Mycroft Holmes urges Sherlock to investigate the death of Secret Intelligence Service clerk Andrew West and the disappearance of a flash drive containing missile plans.
Sherlock refuses and is called to Scotland Yard where Lestrade hands him an envelope containing a mobile phone matching the victim's from "A Study in Pink".
The mobile rings, and the caller – a frightened hostage reading texts from her captor – states that if Sherlock cannot solve the puzzle in twelve hours, a bomb will kill her.
Sherlock realizes the trainers belonged to Carl Powers, a schoolboy who reportedly drowned in a swimming pool 20 year previously.
A second message shows a blood-stained sports car, and another hostage phones, giving Sherlock eight hours to solve this mystery.
After finding that the blood in the car had been frozen, Sherlock announces that the missing man paid the agency owner to help him disappear, and the hostage is freed.
A third message and hostage point Sherlock to the recent death of TV presenter Connie Prince, who allegedly died from tetanus.
He also deduces that Woodbridge worked at a local art gallery that is preparing to display an allegedly "lost" Johannes Vermeer painting, which he says is a forgery.
Realizing that West's death and the missing flash drive were the fifth mystery, Sherlock texts the bomber, offering to turn over the device.
He further singled out Andrew Scott for praise, writing that his "portrayal of Moriarty is a thrilling departure from earlier incarnations of the man".