The second season of Game of Thrones really hit its stride tonight with "Garden of Bones," an episode that heightens the tension in a number of major inter-related conflicts to great effect. It's arguably the season's turning point, the moment where various characters quarrel and draw lines in the sand without really thinking too far in advance of what will come next. That concept is established early on when Robb Stark (Richard Madden) talks to a healer attending to the dead and dying on a decimated battlefield. The Starks have just clashed with the Lannisters, but you can't really tell which side prevailed based on the valley full of indiscriminately decimated bodies.
In this sequence, episode writer Vanessa Taylor firmly establishes that "Garden of Bones" is the point in the season where allegiances are decisively forged and rescinded. The nurse, after sawing off the leg of a gangrenous soldier, incredulously chastises Robb by saying, "You're fighting to overthrow a king, yet you have no plan for what comes after?" "First we have to win the war," Robb firmly replies, but the damage caused by the question has been done. We now know that we're in the thick of the plot, making the episode's climactic finale a dramatic reminder that anything can happen from here on out.
While "Garden of Bones" is full of escalating confrontations, there are two conflicts that advance well beyond the rest. The first is Catelyn Stark's (Michelle Fairley) beef with Petyr "Littlefinger" Baelish (Aidan Gillen), a dispute that's needed squaring up ever since Catelyn's husband, Ned Stark, was killed. The other fight that's majorly advanced is the one between Renly Baratheon (Gethin Anthony) and Melisandre of Asshai (Carice van Houten), the latter of whom fights on behalf of Stannis Baratheon (Stephen Dillane), Renly's brother and rival, for Joffrey Baratheon's (Jack Gleeson) crown.
No other character-defining dilemma heats up as significantly in "Garden of Bones" as Catelyn or Melisandre's, not that of Arya Stark (Maisie Williams), now a captive but otherwise unmolested, and not even that of Daenarys Targaryn (Emilia Clarke), a beleaguered, resourceless leader who's still fighting to keep her Dothraki cabal alive in the desert. Daenarys and her men are miraculously welcomed by the denizens of Qarth, a city whose walls are guarded by the titular garden. So Daenarys, Arya, and even Tyrion Lannister (Peter Dinklage), the last of whom is now openly feuding with Joffrey, all basically survive the events of "Garden of Bones" with relatively non-threatening plot threads dangling over their heads. At least, there's nothing as scary or scarring threatening them by episode's end as there is for Catelyn and Melisandre, two almost-queens (Catelyn's a widow and Melisandre's Stannis's mistress) that advise very different kings.
Melisandre, who serves as the power-hungry Stannis's closest advisor, is the cause of the biggest happening in "Garden of Bones": She gives birth to an evil shadow monster. The scene where Melisandre has Davos Seaworth (Liam Cunningham) ferry her to a remote spot to give birth is the most shocking part of the episode even if it's not the most explicitly violent (Joffrey beats two different women by proxy). We don't yet know how Melisandre's monster will affect Stannis's renewed campaign against Renly, but now we know that the Baratheon brothers' feud has just gotten really serious and really weird really quickly.
By contrast, the most chilling moment in "Garden of Bones" has to be the implicit rather than explicitly chilling moment when Catelyn opens a cask offered to her by Littlefinger that presumably contains Ned's head (we don't get to see it). The way she reacts to Littlefinger's bizarre conciliatory gift is really moving. This is more than just a personal rift between Catelyn and Littlefinger now. The return of Ned's head to Catelyn is sure to have an effect on the Lannister-versus-Stark struggle. Like the way that "Garden of Bones" ends with Melisandre's shadow monster slithering out from between her legs, Catelyn's subplot ends on more uncertain terms than when the episode begins. What comes next obviously matters for every character in the episode. But a tipping point has been reached by Melisandre and Catelyn.