As Purin is forced to navigate the cold, corporate protocols of a psychological evaluation designed to measure her loyalty rather than her health, she realizes she is just another "e;rat in a cage"e; for the management to experiment with. To avoid being locked away indefinitely, she must learn to wear a mask and lie about her own sanity.To this end...seeking refuge from the suffocating pressure of the Ward, Purin finds herself pulled into the chaotic orbit of her eccentric friends once more. From a midnight heist involving hundreds of stolen bathing suits to a narrow escape from a fitness center, she will beforced to wear a mask of sorts (be it figurative or literal).