Last week, we were introduced to the method by which the 12 finalists will be cut down to a more manageable four: Each judge chooses three inventors to mentor, and they have four weeks to spend $50,000 to improve their product. The inventors make a final presentation before all four judges, but only their mentor judge has the power to choose who stays and who goes.

In that episode, ad guy Ed Evangelista picked Erik, the inventor of the Receiver's Training Pole, over Mark (Sackmaster) and Sheryl (In-Brella). This week, the mentor judge was marketing expert Mary Lou Quinlin, and she chose Francisco (the double-seated bike maker), Jerry (portable exercise system) and Darla (multilingual doll).

(Note: There was another all-clips, best-of audition episode that was shown before this one, but I'm not recapping it as the show was filled with mostly repeated footage.)

The show started out like last week's, with a quick glimpse into the personal lives of the inventors. Jerry is a prison correctional officer who lives with his wife and daughter. His job and family are all the more meaningful to him as two of his brothers went into the prison system. A clip from the last round showed inventor Doug Hall questioning whether people will really use Jerry's portable exercise system.

Darla has spent all her time and money for 22 years working on her multilingual doll, Niya, and said her efforts are "a testimony of what can happen when you dare to dream." Nineteen-year-old Francisco immigrated to the United States when he was 12, not knowing the language or even his father, who had immigrated when Francisco was just a toddler.

After the getting-to-know-you sessions, Mary Lou met with each inventor. She told Darla to bring Niya into the 21st century and to update the doll's theme song. Darla held a focus group; one little girl in the group liked Niya but another didn't see anything special about it. Darla looked crushed. But she took Mary Lou's advice to heart and when meeting with a design firm, she focused on giving the doll a larger vocabulary and auditioning young girls to provide the voice for Niya and the song.

For Francisco, Mary Lou advised him to make his bike both hipper and safer. The teen boys in his focus group agreed; their comments focused on a lack of perceived safety and coolness. When Francisco met with his design team, he said he wanted to make the front seat detachable and lower, so the main rider has better vision. He then began to question his market choice: Should he target teens or parents with kids? He was asking excellent questions and making intelligent decisions about his product, but time was of the essence when creating a bike from scratch in less than four weeks.

Mary Lou told Jerry that everybody needs to be able to "lock and load" his portable exercise product. The focus group, mainly women, thought the product was too complicated and that it needed a workout DVD to accompany it. Jerry came up with the smart idea to color code the components to help users put it together correctly, but when meeting with his design firm, he wasn't able to make decisions well and leaned on the team a bit too much.

At the halfway point of their four-week product gestation, Darla was in the studio with a large group of girls recording the new theme song and creating a line of "friends" for Niya. Francisco chose teens as his target market. And Jerry was creating the introduction to his DVD, which wasn't going well due to his nervousness.

The Presentation
When shown in their final prototype, all the inventions looked amazing. The Niya dolls seemed ready for the shelves of Target or Toys"R"Us. Francisco's bike was sleek; the lower front seat looked more comfortable, and the front, piston-driven pedals did away with unsafe chains. And Jerry's exercise system also looked market-ready.

Darla was the first to present her invention to the four judges. She revealed her entire line of dolls, and showed a test video with six- to nine-year-olds playing with Niya. At first, the children weren't too into the doll. They even discovered a flaw which made Niya repeat phrases. But soon, the kids began playing with her happily. Entrepreneur Peter Jones wondered what would set Niya apart from all the other dolls on the shelf. Darla said the music, language and culture. After she left, Ed remarked that it was just a doll, but Mary Lou said Darla has "a fire inside."

Next up was Jerry. He was incredibly nervous. His test video first showed people in an office-building lobby trying the system out; they liked the portability and ease of use. Then, the system was sent on the road with a traveling salesman. At first, everything seemed fine but when the salesman used the portion that hooks to the top of a door, it came back and snapped him in the stomach. It looked very painful, and that "snap" was one of the worst moments I've seen thus far on the show. After this was shown, Jerry just lost it in the presentation. He said they fixed the flaw that caused the snap-back but he kept floundering, even going so far as to attack the other inventions as too niche. It was a train wreck.

Finally, Francisco unveiled his new bike. For his test, he took it to Venice Beach, California. It took some practice for the random people riding it, which didn't bode well. But I realized that the people practicing were adults; put some fearless teenage boys on that bike and they'd be gone before you knew it. In the presentation, Francisco demonstrated that the front seat could easily be removed to make it a "normal" bike, but Peter was disappointed that the front seat couldn't attach to every bike in existence. After Francisco left, Peter was still focused on this point, but Doug noted that Francisco had created a "whole new category of bike."

The Decision
Mary Lou had to make a "really painful" decision. The first person to get cut was Jerry. She mentioned he was a "force of nature" but that his presentation had a lot of bumps in it. His passion wasn't enough.

For Darla, Mary Lou questioned if her 22-year-old idea was past its prime. Francisco, she wondered, could be too young. She questioned if America was ready for his bike and if he was ready to win. In the end, she chose Francisco, which in my humble opinion, was the right way to go. His bike looked amazing; his design choices were smart; the $50,000 seemed well-spent; and the product is revolutionary in its industry.

Next week, we get a two-parter showing the journeys of the remaining six contestants and their mentors, Doug and Peter. Want to know who chose whom? Check out our exclusive interview with Doug Hall, in which he identifies his choices.