WARNING: The following contains spoilers for The Vault, now streaming on Netflix.
The Vault focuses on Thom (Freddie Highmore), an engineering genius who doesn't want to work with oil companies because he wants to change the world. Oddly enough, he's recruited by wealthy salvager, Walter (Liam Cunningham), for "the opportunity of a lifetime" -- robbing an impenetrable vault in the Bank of Spain. This leads to an ambitious heist, as outlined below.
What's the Treasure in the Vault?
Walter's team earlier found a sunken trove in Spanish waters, but the authorities seized it due to maritime law. The gold and other trinkets belonged to Sir Francis Drake, but the Englishman stole them from a Spanish ship, and instead of taking it back to the British crown, he kept it, so it's considered Spain's. The government then takes Walter to court and wins, angering Walter, who wants the three coins in the chest. They have coordinates that lead to a bigger treasure , and while he's rich, this is something he's worked his entire life for. Sadly, not even the British crown are interested in helping him.
What's Special About the Bank of Spain's Vault?
This vault is a technological marvel, despite being centuries old. Any change in the weight of the vault will result in the vault being flooded. This is because it's built like a scale, and as the flooding occurs, the thief inside will be trapped and drowned. This is the complicated part, as the crew has already forged the keys needed to get into the safe, as well as captured the fingerprints of the security boss, Gustavo, for access. Luckily, Thom spots a solution on a night out with Lorraine when they clear their head at a bar, watching a smoky drink being made.
What's the Complication With the Vault?
Thom realizes if they use liquid nitrogen and freeze the scale, they'll slow down atomic activity, so weight shifts won't register. When they enter, Simon infiltrates below the vault and uses 500 liters of nitrogen to do so, allowing James, Lorraine and Thom to walk in after opening the vault. They secure the coins, but the nitrogen thaws quickly, setting off the alarms. The chamber floods, meaning they can swim through the water holes, but it's a dangerous trek only James can make due to his military training.
Who Betrays The Team in The Vault?
Sadly, James is a former MI6 operative and betrays the team for the Crown. He holds them at gunpoint and takes the coins, but Thom has Simon place the canisters on the bottom of the scale. It tricks the vault's weight recognition and shifts the balance down, thus draining the water. This allows Thom and Lorraine to escape through the vents and slip out into the crowd. Gustavo's men can't fire on them, and luckily, Spain scores in the 2010 World Cup. Thom and Lorraine share a kiss thinking they're going to be caught, but as crowd erupts into cheers, the thieves slip away, disguised as Spanish supporters.
Did Walt's Team Really Lose?
James and a MI6 head, Margaret, get the inscriptions and use satellites to track the coordinates to confirm the haul is underneath the Eiffel Tower. Margaret realizes she's been duped, and this ties back to when Walt asked her for help initially. She joked about the Eiffel Tower back when it seemed like her and Walt were friends. He realized something was amiss, so Walt had fake coins made by mysterious associates, anticipating James would betray them for Margaret.
Who is Walt's Danny Ocean?
Earlier, Thom joked he wasn't Danny Ocean from Ocean's Eleven. That title belongs to Lorraine. She's an expert in sleight of hand, and she even steals Thom's watch to remind him of this at their French mansion. He realizes she switched the coins in the vault, with James stealing the fakes. Thom's smitten even more, and as they track the real coordinates down at the end of The Vault, now streaming on Netflix, the coins point them to where Drake's treasure is buried: under the Bank of England in London.