Concerned about an injured animal, the tree house detectives decide to learn more about animals and their care. They visit NASA Kennedy Space Center and its nearby Merritt Island National Wildlife Refuge to meet biologists and ecologists to learn about endangered species, the classification and life cycles of animals, migratory patterns, habitats, and much more.

The tree house detectives visit their friend Dr. D, a retired science professor,

for advice on where to start their investigation. With his direction, the tree

house detectives go on many excursions to speak with various NASA

Researchers, an audiologist, a veterinarian, and even their classroom teachers to get help solving the case. Along the way, they learn more about sound:

what it is, how it is transmitted, and how people and animals hear.

Jacob is eagerly planning his vacation to Fort Jefferson in the Dry Tortugas. He suddenly becomes aware of the possibility that all his plans could go awry if he gets sick! After hearing that a flu epidemic is on the rise, Jacob sets out to quarantine himself in the tree house and will only let "healthy" tree house detectives inside. The other detectives think that Jacob has gone a little overboard but agree to help him learn more about disease and how it spreads.

In The Case of the Challenging Flight, the tree house detectives are onto a new case as they try to win the Egg-tra-ordinary Plane Contest. They do not want to repeat their unsuccessful performance of years past; therefore, they decide that they need to build a better plane. The tree house detectives use their skills in scientific investigation to learn about the four forces of flight and then use their newfound knowledge as they design and construct a plane.

When the tree house detectives try to help solve a noisy aircraft problem, they find that NASA is an expert in the sound business. Come join the detectives as they learn how sound travels, how human beings hear, and what NASA is doing to quiet the skies.

While practicing for a beach volleyball tournament, the tree house detectives discover that the sand on their beach is disappearing! Replacing the sand is too expensive, so the they decide to investigate this mystery.

The tree house detective are eager to go swimming in Mr. E's pool, but a severe storm moves through the area of Wattsville. During the storm many neighborhoods lose electrical power. Once the storm ends, power is restored to most residents, but the tree house detectives notice that the houses across from the tree house are still without power, including Mr. E's house. This mystery becomes their "current" case to solve: The Case of the Electrical Mystery.

When the tree house detectives experience an electrical brownout, they energize into action to learn about Earth's energy budget. The detectives learn that all resources are not created equally and that conservation of nonrenewable and renewable energy is very important.

In The Case of the Galactic Vacation, the tree house detectives receive an assignment to create an "out-of-this-world" vacation. With billions of places in the universe to go, the detectives have different ideas about the best destination.

New discoveries by NASA and a new vision for space exploration create an excitement in the tree house as the detectives set off to learn what it will take to become a space explorer. Join them as they head to Space Camp and NASA to find out if they truly have the "right stuff".

In The Case of the Inhabitable Habitat, the tree house detectives accept the challenge of designing a habitat that can sustain life on Mars. To design an award winning habitat, the tree house detectives decide that they must first learn more about the planet Mars and the various habitats found here on Earth.

The tree house detectives are baffled when they find an unusual object right beneath their feet. They initiate the NASA SCI Files Crime Scene Investigation Team and enlist the help of NASA to help determine the origins of this foreign object. As they get to the heart of the "matter," they learn that all materials are different and that technology can be a very useful tool.

Each day, for no apparent reason, the morning and evening sky blazes with a brilliant deep red color. In The Case of the Mysterious Red Light, the tree house detectives are determined to solve this mystery, but are puzzled as to what phenomena could be causing the bright red sunrises and sunsets.

Floating tennis shoes and oil globs wash up on the beach to set the tree house detectives in motion to investigate a unique world under the sea. Join them as they dive into learning about ocean floor topography, currents, ocean zones, and more.

The tree house detectives are eager to go to the physics fair at Busch Gardens, but they are worried that bad weather will keep them from attending. Just off the coast of Africa is a tropical wave, and even though it looks really far away, they decide they need to learn more about weather forecasting just to make sure. They are glad they made that decision when they find out that even more is at stake as KSNN announces the winners of the environmental contest. They won!

The tree house detectives are eager to win the Presidential Physical Fitness Award, but one of the detectives is not quite up to the challenge. They decide that it is time for a little research to learn more about being fit. They visit NASA to learn more about muscles, bones, and physical activity and why fitness is the key to space exploration.

Accidents happen and Jacob has broken his foot. He is eager to get back into the tree house and join his friends, but the cast on his foot prevents him from climbing the ladder. The tree house detectives decide that devising a plan to get Jacob safely into the tree house will be their next case, and so begins The Case of the Powerful Pulleys.

The tree house detectives' green thumbs are tested as they attempt to grow award-winning plants for the upcoming fair. The tree house becomes a green house as the detectives experiment with soil, light, plant life cycles, and genetics to grow the perfect plant.

As Bianca and Kali arrive to meet the rest of the tree house detectives at the NASA auditorium for an awards ceremony, they learn that Dr. D, Jacob, and Katherine are having minor traffic problems. Convinced that they have plenty of time to get to the ceremony, and with not much else to do while they sit and wait, the detectives decide to work on their latest school project. The assignment is to come up with an idea for what transportation will look like in 100 years.

One afternoon, the tree house detectives feel their tree house shake. They wonder what could have caused the vibration. Unsure whether they had just experienced an earthquake, the tree house detectives decide to make the unexplained vibration the subject of their next case and set out to solve The Case of the Shaky Quake.