Ep 1. The Heart of the Truest Believer

Once Upon a Time season 3 episode 1, titled "The Heart of the Truest Believer," opens with Henry, Emma's biological son, who has been taken by Greg and Tamara, the two villains of the previous season. Henry is in a remote jungle in Neverland, a place where villains are exiled once they are defeated by heroes. Tamara and Greg believe that Henry is the "Heart of the Truest Believer," which according to them, is the most powerful substance in the world. They plan to extract it from him by any means necessary to carry out their evil plans.

Regina, Emma, Mary Margaret (Snow White), David (Prince Charming), Rumplestiltskin (aka Mr. Gold), and Hook head to Neverland to rescue Henry before it's too late. They all travel by ship, where much bickering and misundersting comes to the forefront as they all have their own hidden agendas. Emma, who had given up Henry for adoption many years ago, feels that she's failed as a mother and wants to make amends by getting Henry back from his captors. Regina, who is Henry's adoptive mother, wants to prove that she loves Henry and is willing to do anything to protect him. Mary Margaret and David want to reunite with their grandson and help in any way they can, while Rumplestiltskin wants to use the opportunity to find his son who he lost many years ago. Hook is also aboard the ship, looking for a way to exact his revenge on Rumplestiltskin for a past betrayal.

As the group reaches the treacherous shores of Neverland, they are quickly greeted by the Lost Boys, who seem to be children, are unable to age, and most importantly, are willing to do anything to protect their home and their leader, the infamous Peter Pan. Pan is the mastermind behind everything happening in Neverland, and he also has a mysterious interest in Henry, the "Heart of the Truest Believer." The Lost Boys capture the group and take them to their hideout.

Meanwhile, Tamara and Greg's true intentions are revealed. They have plans to destroy magic from the world by using Henry's "Heart of the Truest Believer," which they believe will give them the power to control everything that is magical. They try to extract the heart from Henry, but they can't seem to get to it as Henry's pure and unwavering belief in magic is what's keeping the heart intact. They decide to hold Henry captive instead until they figure out another way to get to his heart.

While being held captive by the Lost Boys, Mary Margaret and David strike up a conversation with one of the boys, who reveals that Peter Pan is not the good guy that fairy tales make him out to be. Peter Pan has been playing a long game with everyone, manipulating and controlling everything that's been happening in Neverland. The group realizes they need to get to Pan to rescue Henry and end his reign of terror.

As the group sets out to confront Peter Pan, they realize they need to get past the obstacles of the island. They find themselves in a treacherous jungle filled with traps and obstacles. Along the way, they encounter various characters from classic fairy tales such as mermaids and giants.

Meanwhile, Henry manages to escape from Tamara and Greg's captivity and finds himself face-to-face with Pan. Henry utterly believes in everything he's been taught in his fairy tale books and believes that Peter Pan is a good guy who just needs guidance. Peter, impressed by Henry's beliefs, convinces him to stay with him and become the new leader of the Lost Boys. Henry agrees, thinking he's fulfilling his destiny.

The episode ends with the group arriving at Pan's hideout, ready to confront him and rescue Henry. They find out that Henry is not only missing but is now potentially on the opposite side. The episode ends with the group looking out into the distance, ready to face whatever consequences may come from their latest mission.

Overall, "The Heart of the Truest Believer" sets up so many different storylines for the season that it's hard to keep track of all of them at once. However, it introduces a lot of new character dynamics and creates a new world and rules to explore. It's an exciting start to a season full of magic, adventure, and classic fairy tales.