Bianca is very concerned about her appearance as she can be seen putting on things like perfume and beauty powder. She's very beautiful, elegant, and graceful, which sets her apart from other Disney females. Despite her slight obsession with her appearance, she is very kind-hearted, compassionate, caring, and very unshallow. It is also shown that she is quite daring and has a love for adventure, as shown in certain scenes in the movies. She also has a strong sense of duty when it comes to her position in the Rescue Aid Society, placing her duty before anything else.
AppearancesPenny." Showing concern for Penny, Bianca begs for the chairman to let her have the assignment. The chairman is hesitant at first but decides to let her go as long as she has a co-agent. Many of the male Society members volunteer, but ultimately, Bianca chooses Bernard, believing that the two of them will be a great team.
Bianca and Bernard begin their search for clues at Morningside Orphanage where Penny once lived. Inside the orphanage, they meet a cat named Rufus. Rufus explains that the last time he saw Penny was after she did not get adopted by couples visiting the orphanage. He goes on to say that Penny had been offered a ride by a sinister woman named Madame Medusa, the owner of a trashy pawn shop near the orphanage. Rufus believes that Medusa is most likely responsible for Penny's sudden disappearance.
Next, the team goes to Medusa's Pawn Shop. The shop is empty when they first enter, but soon Bianca finds one of Penny's school books. Bernard reasons that Penny must still be hidden somewhere in the shop. However, before they can investigate further, the telephone rings. The mice quickly hide as Madame Medusa enters and answers the phone. The mice overhear a conversation between Medusa and her accomplice Mr. Snoops. Medusa immediately asks whether Mr. Snoops had found "the diamond". When Snoops reveals that he had not and that Penny had been sending messages in bottles, Medusa is angered and decides to fly to Devil's Bayou that very night. Bernard stows away in Medusa's suitcase as she carelessly packs. Bianca tries to get in the suitcase but cannot and ends up riding on the floor of Medusa's car as it speeds down the street. The car (a convertible) makes a sharp turn and the suitcase falls out taking Bianca and Bernard with it
Although Bernard protests due to the abundance of the unlucky number 13 on the flight, Bianca flies with him on Orville the albatross to Devil's Bayou. When in the process of landing, Penny escapes from the clutches of Madame Medusa, so she releases her 2 pet crocodiles, Brutus and Nero, to find her as well as going out in her swamp mobile. She orders Mr. Snoops to set off fireworks to illuminate the swamp for her. Orville is hit by one of them and crashes, although the two mice are unhurt thanks to Miss Bianca's umbrella. They meet up with two friendly bayou mice who would like nothing more than to rid the swamp of Madame Medusa and witness Penny being recaptured by Brutus and Nero. The bayou mice lend them their dragonfly Evinrude to use as a motorboat.
When they arrive at Madame Medusa's riverboat hideout, they hide from Medusa and her henchmen, but as Brutus and Nero are passing them, Brutus smells Miss Bianca's perfume. He and Nero chase Miss Bianca and Bernard through the ship and ultimately into a large organ. While in there, Brutus/Nero, whichever one plays it while the other waits in ambush, starts playing the organ, which causes Bernard and Bianca to float up out of it in their attempt to eat them. Finally, Bernard flies out of the organ and Brutus/Nero catches him in his mouth, to Bianca's horror. Medusa then arrives, telling her pet crocs to stop with the noise and hits Brutus/Nero with her cane causing him to spit Bernard out. Medusa then freaks out and attempt to kill him and Bianca along with Snoops by shooting them. When Medusa's shotgun jams, Bianca and Bernard take the opportunity to run, only to be shot at the last minute by one of Medusa's buckshot rounds. Luckily, the two survive and end up in the bayou and are found by Evinrude.
After being rescued, Bianca furiously wishes she was big enough to take on Medusa by saying quote, "Oooooh, if I was only a ten-foot mouse, I'd show her." Bernard then doubts that he and Bianca can rescue Penny because they are merely two little mice, but she reminds him that the Rescue Aid Society is depending on them and that they can't quit after hearing the theme song in her head.
Bianca and Bernard see Penny out on the balcony of the ship. When she goes inside to her room, the two mice observe her from outside of a window as she prays. As Penny starts crying, the two mice are now inside and meet Penny and Bianca consoles Penny because they have come to help her. Penny seems excited because her message (that was sent earlier in the beginning of the movie) had reached someone, but them she asks why she and Bernard didn't bring someone bigger with them (such as the police). Bianca then declares that the three of them should work together and have a little faith.
Together, Penny, Bernard, and Bianca concoct a plan to escape the bayou that night by first trapping Brutus and Nero in an elevator, followed by escaping in Medusa's swamp mobile and keeping her preoccupied by shooting off Mr. Snoops' fireworks in her room.
With the plan in motion, Bianca tells Penny to get dressed so they can put the plan into action. Bernard tells Evinrude to get Ellie Mae and the other swamp critters, but the plan is put on hold when Evinrude is cut off by a swarm of bats.
In the Black Hole, Bianca, along with Bernard and Penny, set off to find the Devil's Eye. Bianca is dreaded by the appearance of the cave. Penny informs her that it as once a pirate's cave. When Bianca asks Penny how she knows this, she answers by showing her the skeletal body of what was once a pirate with a sword stabbed in its chest.
After rescuing Bernard from falling into a dark hole in the cave, which is where the tide comes in, Bianca and Bernard continue to search for the Devil's Eye. When Penny holds her lantern up to a skeleton's head, they discover the Devil's Eye inside of it. The two mice try to get the diamond through the skull's left eye, but the diamond is too big. Luckily, with the help of Penny and a pirate sword, they are able to get the diamond out of the skull through the mouth and just barely escape the cave after the tide comes in and nearly drowns her, Bernard and Penny in a whirlpool.
Later, Medusa is about to escape Devil's Bayou with Penny's Teddy bear (which she has stuffed the diamond inside of), but Bianca and Bernard trip her with a rope.
After Penny manages to get her Teddy bear back and commandeer Medusa's Swampmobile, Bianca is seen attempting to help her start the vehicle. With help from Bernard and the swamp critters, they manage to start the Swampmobile, but Medusa chases after them by holding onto a rope attached to the back of the Swampmobile, and later using Brutus and Nero as water skis, whipping them with the rope, angering them. Bianca soon sees they are about to crash into the sinking riverboat, but Penny swerves just in time, causing the rope to snap and send Medusa crashing into one of the smokestacks, leaving her at the mercy of Brutus and Nero as Bianca, Bernard, Penny, and the swamp critters escape on the Swampmobile.
Back at the United Nations Headquarters in New York City, Bianca and Bernard learn on the news that the Devil's Eye has been donated to the Smithsonian Institute in Washington, D.C., while Penny has been adopted by a new mom and dad, thanking Bianca and Bernard, much to the reporter's confusion, but to the amusment of the Rescue Aid Society delegates. Evinrude then arrives with another call for help, and Bianca volunteers herself and Bernard for the mission, taking off on Orville once more with Evinrude joining them, despite it being Friday the 13th and with a nasty blizzard blowing through NYC at the time.
At the start of the sequel, Bianca and Bernard are at a fancy mouse restaurant, when after Bernard wanders off to retrieve his proposal ring to Bianca to marry him, Bianca is delivered a message from the Rescue Aid Society by the head waiter, Francois, requesting her and Bernard for a mission to Australia to rescue a young boy named Cody who had been kidnapped by the wanted poacher McLeach. When Bernard returns, he believes that Bianca accepted his marriage proposal, but upon returning to R.A.S. Headquarters, he discovers that he will be going with her on a mission to Australia.
Heading to Albatross Airlines to seek out Orville for a flight to Australia, they find that Orville has left the business in the hands of his younger brother, Wilbur, who takes some convincing to agree to take Bianca and Bernard to Australia, especially throughout the blizzard raging through NYC at the time. They are soon forced to hitch a ride on a jumbo jet to make it all the way to Australia. Flying past the Sydney Opera House and the city proper, they then head for the Australian outback to meet up with the R.A.S. regional operative there, a kangaroo mouse named Jake.
When they arrive at the airport where Jake works, Jake is at first annoyed by Wilbur trying to land despite warning him the runway is too short, calling him a "Crazy Yank", but is soon smitten upon seeing Miss Bianca, and is more than happy to help them rescue Cody. While Wilbur is taken to the hospital to have his spine fixed, Bianca and Bernard go with Jake to find McLeach's hideout. At one point, when they are alone, Bernard attempts to propose to Bianca again, but is interrupted when Jake arrives to tame a snake named Twister. From there, Bernard's repeated attempts to propose to Bianca are ruined in some way by Jake as they continue on their mission to save Cody.
That night, Bianca is riding on the firefly with Bernard and Jake on their travels to the fireflies.
Upon reaching McLeach's lair, they take cover on the door as McLeach pushes Cody out and tells him that his friend, Marahute, has been killed by another poacher, leaving her eggs without a mother to care for them. This is merely bait to get Cody to lead McLeach right to Marahute's nest. Bianca, Bernard, and Jake hop aboard McLeach's truck and ride it to Marahute's nest. Once there, they climb down to warn Cody that McLeach tailed him, but when Marahute appears, returning to her nest, McLeach captures her, along with Cody, Bianca, and Jake.
Taking them to Crocodile Falls, McLeach prepares to feed Cody to the crocodiles, but finds his truck suddenly disabled by something swipping the keys, forcing him to use his scoped rifle to sever the rope holding Cody instead. It turns out that Bernard had caught up to them and swipped the keys, which he then gives to Bianca and Jake to free Marahute while Bernard dealt with McLeach and Joanna. They free Marahute just as Bernard's attempts to save Cody fail, and the two of them are about to go over the waterfall to join McLeach in death, but Marahute saves them just in time. As Bianca congratulates Bernard for his heroism, Bernard makes certain this time his proposal is not interrupted, and asks Bianca to become his wife. She happily accepts as Jake looks on with respect, and Cody has Marahute fly them home to his house.
Bianca made occasional cameos on House of Mouse.
Bianca, along with Bernard, made appearances at Walt Disney World and Disneyland in the years following the original film's release. They currently don't make appearances at the American parks, although she and Bernard continue to appear regularly at the Tokyo Disney Resort.
- Miss Bianca's Hungarian nationality comes from her voice actress, Eva Gabor, who was born in Hungary.
- Her voice actress Eva Gabor has also voiced Duchess.
- "Bianca," which is the singular feminine form of "Bianco," is Italian for "white," appropriately describing her fur color.