Lupin is hired by his old friend Gaston to steal a certain painting - a Picasso forgery ostensibly painted by Gaston's grandchild - from the vault of Mr. B, a compulsive art collector. Lupin succeeds in his heist, but discovers in short order that the Gaston who hired Lupin was an impostor, since the real one died a month ago, and that the painting is the hiding-place for a notebook containing information about high-level crimes hushed up by the French police, evidence which would topple a number of high-level personnages if its contents went public. For this, he and Jigen end up chased by the DSGE and Albert, an old - and unfavored - individual from Lupin's past.