One night after returning from the Braille Institute, Wallace Curtis, who is blind, is disturbed when his seeing eye dog begins to bark upon entering their apartment. Wally smells gas fumes throughout the apartment, which he shares with his mother Edna, and as he stumbles around, turning off the gas stove in the kitchen and opening windows, he calls for Edna. He finds her body on her bed, and as he is telephoning for an ambulance, landlady Mrs. Kelly enters and confirms that Edna is dead. Lt. Andy Doyle, of the Los Angeles Sheriff’s Department, investigates, and reads to Wally the typewritten suicide note left by his mother. In it, Edna urges Wally to use her life insurance money to have an operation performed by Dr. Hastings, a renowned eye surgeon. Wally explains that he was blinded five years earlier when he accidentally took a bottle other than his eye drops out of the medicine cabinet and put the wrong medication in his eyes. Edna was partners with Raymond Wilkins in a clothing company, Playtime Togs, which had fallen upon hard times, and Wally speculates that the company’s troubles may have prompted his mother’s suicide. As Andy is leaving, Wally’s girl friend, Phyllis Baxter, a designer for Playtime, arrives to comfort him. Andy then questions Mrs. Kelly, who insists that she heard Wally and Edna having a loud argument recently, during which Edna declared that because she had borrowed so much money against her life insurance, she would not be able to borrow any more for another eye operation. Beginning to doubt that Edna’s death was suicide, Andy continues to investigate. Andy learns that Wally and Phyllis were to be married before Wally’s accident, but that since then, Wally has postponed the marriage because he does not want to burden Phyllis. Andy interviews Wilkins and George Caldwell, Edna’s attorney, who reveals that Wally was Edna’s sole heir, even though the estate contains only the life insurance policies. Andy inquires why Edna left no other assets, and Wilkins explains that when receipts are down, the partners pay their employees but draw no salary themselves. While at the offices, Andy surreptitiously takes samples from various typewriters and learns that the suicide note was written on Phyllis’ machine. Andy also discovers that Edna had been anticipating a luncheon with a New York colleague, Harry Woodruff, and wonders why someone about to commit suicide would write a reminder of an upcoming event on her calendar. While Andy’s sergeant, Mike Duncan, tries to find Woodruff, Andy continues to question Wally and Phyllis, often turning up at the hospital where Wally is recuperating following his surgery. Andy has discovered that it was Edna who was responsible for the accident that blinded Wally, and wonders if revenge, as well as money, was a possible motive for Wally to have killed his mother. Meanwhile, Wally learns that Edna’s insurance policies are worth only five thousand dollars, and that all of her heirloom jewelry is missing from her safe-deposit box. Although Phyllis speculates that Edna sold the jewelry without telling Wally, Wally is suspicious, as Caldwell also had access to the box. At the end of the three weeks, Wally’s bandages are removed and his sight is completely restored, although he tells only Phyllis the truth, letting everyone else believe that he is still blind. Wally intends to use his new sight to investigate his mother’s death, and has Phyllis drive him to Caldwell’s that evening. Unknown to the young couple, as they ring Caldwell’s doorbell, the lawyer lies dead inside his apartment. The next morning, Wally hears a radio report about Caldwell’s death and runs away from the hospital, prompting Andy to search for him at Playtime’s office. Phyllis is stunned by news of Caldwell’s murder and assures Andy that she and Wally are innocent. Wally questions Mrs. Kelly, who admits that the argument she heard could have between Edna and another man, and that a man frequently came to visit Edna when Wally was out. When Mrs. Kelly mentions that she saw a “flashy blonde” waiting for the man, Wally realizes that she means Vera, a model for Playtime, and that the man must be Wilkins, who has been secretly dating her. At the police station, Andy and Mike interview Woodruff, who states that Edna, a longtime customer, had switched to another silk supplier. When the curious Woodruff investigated, however, he found that the new company, Regal Crest, did not exist. Meanwhile, Wally follows Vera and Wilkins to a nightclub, where he learns from Kenny, the bartender, that Wilkins has been lavishing money on Vera. After Wilkins escorts Vera back to her apartment and leaves, Wally enters and admires Vera’s new bracelet, which he recognizes as his mother’s. Vera is astonished to realize that Wally has regained his sight, and horrified by his suggestion that Wilkins has been altering the company’s books, which then led him to murder the suspicious Edna. Wally leaves, but when he telephones Phyllis to meet him, the police follow her and take them to the station. There, Andy reveals that he has summoned Playtime accountant Dave Glennon, based on Woodruff’s information, and they all head to the office to search for evidence of Wilkins’ embezzlement, as it was he who ordered Edna to switch to Regal Crest. There, they discover that the many checks made out to Regal Crest were endorsed by someone named Harry Apperson. Andy collects samples of Wilkins’ handwriting to check against both Apperson’s signature and the signature on the suicide note, then leaves with Dave to examine the Playtime warehouse. As suspected, the warehouse is empty, further proving that Wilkins had been paying a front company he owned for nonexistent goods. While Wally and Phyllis are at Playtime, Wilkins visits Vera and learns of Wally’s accusations. Upon hearing that Wally was interested in the company’s books, Wilkins goes to the office to cover up the evidence of his crimes. When he surprises Phyllis, Wilkins admits to killing Edna because she suspected the truth, and Caldwell because he was blackmailing him. Just as Wilkins is about to strangle Phyllis, Wally attacks him. Wilkins knocks Wally down and attempts to escape, but is trapped by the returning Andy, Mike and Dave. Wilkins tries to hide in the darkened storeroom, but Wally, accustomed to the dark, is able to located and subdue him. With Wilkins under arrest, Wally and Phyllis walk off arm-in-arm, and Andy offers to treat Dave to a beer.