On June 23, 2018, an innocent outing quickly turns perilous for the twelve boys of the junior football team "Wild Boars" and their assistant coach, Ekkaphon Chanthawong (Teeradon Supapunpinyo). After concluding their practice in Ban Chong, located in Chiang Rai province, the group decides to explore the Tham Luang cave. Little do they know, this adventure will take a dramatic turn. The caves, known for their depth—particularly Chamber 3, which is 800 meters from the entrance—begin to flood unexpectedly as rain pours down.
The heavy rains, which were totally unforeseen and outside of the typical monsoon season, catch everyone by surprise. When the boys fail to show up for a birthday party later that day, their anxious families rush to the caves where they discover the entrance is submerged and their children are nowhere to be found, with their bikes left stranded at the mouth. Alarmed, the parents immediately notify the authorities. News quickly reaches Governor Narongsak Osatanakorn (Sahajak Boonthanakit), who promptly calls in the Thai Navy Seals to initiate a search.
Under the leadership of Captain Arnont (Teerapat Sajakul), the Royal Thai Navy SEALs spring into action. Despite their best efforts, they find the dive into the cave to be extraordinarily demanding. Vernon Unsworth (Lewis Fitz-Gerald), a local British caver with extensive knowledge of the cave system, steps forward, offering his assistance and counsel to the authorities. His meticulous mapping of the cave on paper provides crucial insights. During the first rescue attempt, the dive reaches Chamber 3 but has to turn back due to flash flooding.
As days pass, more agencies mobilize, with a relentless effort dedicated to pumping water from the caves. However, the numerous sinkholes on the mountain continue to feed the rising water, rendering the attempts futile. A remarkable wave of solidarity emerges, as thousands of Thai citizens and international volunteers join the rescue mission, eager to lend a hand.
By Day 5, British divers Rick Stanton (Viggo Mortensen) and John Volanthen (Colin Farrell) make their way into the cave, bravely navigating through challenging conditions to reach a stalactite tunnel and a T-junction. They bravely assist a stranded rescuer on their return, showcasing their commitment and courage amidst the chaos.
Despite ongoing efforts, by Day 7—still no sightings of the boys or their coach. The governor convenes a meeting with the involved teams, cautious of the ongoing rain which hinders operations. John and Rick volunteer to dive once more, but the governor prioritizes safety over haste.
As the rescue operations continue, a water technician discovers issues with the sinkholes and successfully garners support from local farmers to redirect water, albeit destroying crops in the process. Then, on Day 9, the rains finally subside. The governor makes the decision to allow Rick and John to continue despite the Navy Seals still needing time to prepare.
Navigating to the T-junction, they ultimately reach Chamber 9, approximately 2500 meters from the entrance, where they discover all thirteen boys and their coach alive! However, tension escalates as Rick realizes that waiting for water levels to drop could lead to tragedy. The boys might succumb to panic during the 2.5-kilometer dive back, making any exit nearly impossible without intervention.
As the days drag on, the Thai teams strive to provide nourishment and essentials for the boys. However, time is against them, as oxygen levels dwindle dangerously low. By Day 12, frustration mounts among the families, and progress seems stymied.
Finally, with the realization that the boys must be rescued through a challenging dive, John and Rick reach out to Dr. Richard Harris (Joel Edgerton), along with fellow divers Chris Jewell (Tom Bateman) and Jason Mallinson (Paul Gleeson). They coordinate efforts to supply the boys with food responsibly.
As the rescue timeline presses on, tragedy strikes on Day 15 when a former Thai Navy Seal, Saman Kunan (Sukollawat Kanarot), tragically drowns during a supply mission. As the team grapples with the hazards of the operation, questions arise around the use of anesthesia for the boys, each decision fraught with risk.
However, on Day 16, with formal permissions secured, the divers begin the painstaking task of carrying the boys to safety one by one while ensuring they remain sedated throughout the rigorous underwater journey. An unexpected outcome follows as all boys emerge unscathed.
With joy and relief, parents embrace their children once they've time-tested all 18 days of immense uncertainty. The climactic close of this harrowing tale features the boys celebrating the birthday that was to take place on the day of their cave venture. As the credits roll, the film honors the heartfelt contributions of Saman Kunan and Beirut Pakbara, another Navy Seal who passed away post-rescue due to complications. The selfless action of divers, volunteers, and locals—boosted by the diversion of 56 million gallons of water from the cave—ensured a reunion for a team that will be forever etched in the annals of hope and resilience.
