An expedition of three men who have come together begins! Actor Cha Seung-won teams up with Juyeon from THE BOYZ and actor Kim Sung-kyun. They travel to Mexico, where they will explore the culture and history of Ancient Maya and how it is preserved today. However, it is not just a trip that awaits them. It looks like they have a mission to go on as well.

In order to receive the first key, the brothers must experience Mayan food. They travel to Zinacantan to complete their first mission. There, they meet a Mayan family who still maintains the traditional ways of the Mayans. Thanks to the hospitality of the Mayan family, they get to experience various Mayan dishes as well as how to cook it. What other experiences will they have?

After successfully completing the mission for the first key, it's time for the second mission. To complete the mission, the brothers head over to the market. While there, they pick up some ingredients for the Korean meal they will be cooking for Alberto and his family. Yesterday, the members sat front row, center to watch Helena cook a Mayan meal, and today, Helena and her family watch as Chef Cha whips up a delicious Korean meal with a Mayan twist.

The mission for the third key begins at Tonina. The brothers visit the Mayan pyramids located at Tonina and explore the ruins. They also visit the Tonina Museum to look at artifacts and to find hints related to their fourth mission. Back at their lodging, they prepare a Korean dinner with sausage stew and tteokbokki, which they improvise with local ingredients.

The Maya exploring party leaves San Cristobal and heads to Tulum for its fourth mission. But before doing so, the three members visit a cafe that prepares cocoa drinks in the traditional Mayan way. Back at the lodging, they attempt to recreate the traditional cocoa drink by themselves. On the next day, they explore Tulum and discover its secrets.

The Maya exploring party continues to explore Tulum. They visit Cenote Lol-ha and have a good time exploring the sacred spring of Maya. However, Juyeon unexpectedly comes down with a cold. To invigorate their youngest member, Seung-won and Sung-kyun attempt to recreate Juyeon's favorite food, jjamppong, in Mexico, using ingredients from the Mayan sea.

The Maya exploring party once again explores the food of Maya. They visit a village of Mayan descendants in Coba to join their lunch and try out more traditional Mayan food. To express gratitude, the Maya exploring party cooks a traditional Korean dinner, made with both Korean and local Mayan ingredients, for the Mayan family.

The Maya exploring party heads to Uxmal, a city of deities, to further explore the myths of Maya. Afterward, the members try various traditional Mayan cuisines at a Mayan restaurant. After sunset, they go to a plaza in Merida to watch a game of pok-ta-pok, an ancient Mayan sport and ritual. At last, they finish the day by cooking Korean food.

The Maya exploring party heads to Chichen Itza for its last day in Maya. The members explore historical sites in Chichen Itza and learn about ancient Maya’s amazing technology and astronomy. Afterward, they look back on their expedition before receiving the last key and uncovering the secrets behind the Mayan treasure box. What secret awaits them in the end?