When efficiency expert Richard Sumner comes to the research department of the Federal Broadcasting Company to evaluate work patterns, his eccentric behavior piques the curiosity of researchers Peg Costello, Sylvia Blair and Ruthie Saylor. Bunny Watson, the quick-witted, sharp-tongued head researcher, begins to worry when Sumner informs her that he is a methods engineer whose goal is to improve the man-work hour relationship. After observing the department, Sumner confers with Mr. Azae, the head of the network, about computerization, and Azae asks him to keep the project a secret. Meanwhile, Bunny admires a gown she has purchased in the hope that Mike Cutler, her boss and suitor of seven years, will invite her to a country club dance, prompting the wise-cracking Peg to counsel Bunny that she has made herself too available to Mike, who treats her "like an old coat." Soon after, Mike appears, and after asking Bunny to look over his department financial report, offhandedly invites her to the dance and a weekend in the country. Afterward, Sumner invites Bunny to lunch and she has visions of dining at a posh hotel until Sumner escorts her to the blustery rooftop of the office building and hands her a sandwich. Sumner then gives Bunny an ability test, and she astounds him by answering every question perfectly. Bunny quips that she has researched Sumner and discovered that he is the inventor and patent holder of EMMARAC, an electronic brain. Impressed, Sumner compliments Bunny by calling her a "rare tropical fish." After lunch, Bunny pumps Smithers, the office gossip, for information about Sumner. Upon returning to the office, Bunny is breathlessly informed by Peg that Sumner has come to replace them all with his mechanical brain. After Bunny reassures Peg that no machine can do their job, Peg counters that half the payroll department was dismissed after EMMARAC was installed in their division. As Sumner daily haunts the research department, the team becomes extremely paranoid. On the eve of the big weekend, Mike drops into Bunny's office to break their date because he has been asked to accompany Azae to Chicago as a result of "his" exemplary financial report. At the end of work that afternoon, Bunny and Sumner encounter Smithers in the hallway. It is storming outside, and consequently, Smithers offers them a ride with his squalling family. After Smithers drops them off in front of Bunny's apartment building, Bunny invites the soaked Sumner in for dinner and gives him a robe to wear that she has bought as a Christmas gift for Mike. They dine convivially, dressed only in their robes, and when Sumner walks into the kitchen to fetch dessert, Mike rings the doorbell and explains that his plane has been grounded. When Sumner appears, the pompous Mike is shocked to find Bunny entertaining another man. Peg rings the doorbell next, and when Mike apologizes for his unseemly behavior, Bunny thinks Mike is about to propose, but instead, he disappoints her once again. At the office Christmas party, the research staff laments the fact that this will be their last office party. As Peg and Bunny giggle, slightly tipsy from an abundance of champagne, Sumner scrutinizes his budget and Mike returns from Chicago. When Bunny presents Mike with a set of bongo drums as his Christmas gift, he starts to propose but is summoned to Azae's office. In Mike's absence, Sumner pounds the drums as Bunny sings. Sparks begin to fly between Bunny and Sumner, and Bunny accuses Sumner of never marrying because he is in love with EMMARAC. Mike then returns, bubbling with the news that he has been promoted to vice president. When Mike announces that he and Bunny will leave for the coast on Tuesday to be married, Bunny makes excuses about why she cannot possibly leave New York, and Mike accuses Bunny of being involved with Sumner and angrily storms out of the office. Sumner then merrily invites the entire office for a drink, but the air of congeniality is shattered when the coldly efficient, condescending Miss Warringer arrives from Sumner's office to arrange for the installation of EMMARAC. Soon after, EMMARAC arrives, overseen by Miss Warringer and her many prohibitions. When their pay envelopes arrive stuffed with pink dismissal slips, the staff sadly begins to pack up their desks and refuse to answer the phones, which are ringing off their hooks with research questions, forcing the befuddled Miss Warringer to deal with the onslaught of calls. Sumner is puzzled by the staff's lack of cooperation, and after EMMARAC goes berserk, Miss Warringer breaks down in hysterics and runs screaming from the office. After receiving his pink slip, Sumner discovers that the entire building has been fired by the payroll computer. Sumner then explains that EMMARAC was never intended to replace the research department, only to help them do their job, but the project was kept secret because of an impending merger with another network. After Sumner teaches Bunny to use EMMARAC, she fondly pats the machine. When Mike, bearing roses, enters Bunny's office, Sumner calls her out of the room and asks EMMARAC if Bunny should marry Mike or him. Asserting that EMMARAC would always come first in Sumner's life, Bunny pushes the destruct button to prove her point. As Mike leaves the roses on Bunny's desk and silently departs, Sumner repairs EMMARAC and then hugs Bunny.