"Buyout"
Season 5, Episode 6 

The methylamine plan worked, and now Jesse and Mike have decided to sell it to Declan, a meth distributor. But he refuses to just buy Jesse and Mike's share: he wants Walt's share as well, to completely take Blue Sky out of the market. Jesse runs to Walt's and asks him to join the negotiations—which would bring an end to the business. Walt thinks back to the time he sold his stake in Gray Matter Technologies for $5,000, long before the company was worth $2.16 billion. Fueled by that regret, he tells Jesse that he isn't in the meth or money business: he's in the "empire business."

Later, Walt rushes down to Vamanos, their "fumigation" company, to retrieve the methylamine. Mike catches Walt, and zip-ties him to a radiator so he can sell off the entire batch of methylamine without Walt's consent. Walt tries to free himself by using a broken pot, but fails. Then, he uses electricity from a socket to create an electrical arc that melts the plastic and frees him. Mike returns, finds the methylamine gone and Walt hiding in the office. Mike places a gun to Walt's face, trying his hardest not to pull the trigger, then Walt explains his plan where "everybody wins."