Darwin and Newts are tidying up the treehouse and causing a real mess. Burpee gets upset, and heads to the big swamp to see his frog friend Croakette. But the swamp is far away and frogs need water - can Darwin and Newts save Burpee in time?
When Darwin and Newts use the zip line to take Heni to see an incredible giant snail, a malfunction is overcome thanks to their newfound knowledge of magnets.
When Burpee gets sore legs from dancing with Croakette, Darwin and Newts help by learning how to catch bugs for his lunch. In the process, they observe that the sun casts shadows, which helps you tell the time of day.
Darwin and Newts want to touch a rainbow so go on an adventure to catch one. They discover what is needed to make a rainbow, and Heni creates one especially for them.
Darwin and Newts are puzzled when no one shows up for Wapiti's Antler Day party. Finding some footprints they follow them to find where everyone has gone.
Darwin records a butterfly's life cycle when his swan plants attract a caterpillar that becomes a chrysalis, while Newts figures out how to paint a butterfly with symmetrically-patterned wings.
Darwin and Newts learn about sound and vibration when Newts becomes obsessed with drumming. Darwin takes what they've learned to make a home-made telephone.
Newts tries to preserve some ice from a frozen pond to make Burpee and Croakette an ice skating rink, and she and Darwin learn about the different states of water.
Newts and Heni go searching for gold to complete Darwin's rock collection, while Darwin stays at the treehouse to grow crystals from his new crystal-growing set.
Darwin and Newts follow an apple tree through the seasons, becoming worried when it becomes sick in winter but learning that the tree's changes are part of a natural cycle.
When Darwin's garden starts drying out during a hot, rainless summer, the kids try different methods of watering it, eventually building an aqueduct using the water from Burpee's pond.