This episode explores the wave theory of light as studied by mankind, noting that light has played an important role in scientific progress, with such early experiments from over 2000 years ago involving the camera obscura by the Chinese philosopher Mozi. Tyson describes the work of the 11th century Arabic scientist Ibn al-Haytham, considered to be one of the first to postulate on the nature of light and optics leading to the concept of the telescope, as well as one of the first researchers to use the scientific method. Tyson proceeds to discuss the nature of light as discovered by mankind. Work by Isaac Newton using diffraction through prisms demonstrated that light was composed of the visible spectrum, while findings of William Herschel in the 19th century showed that light also consisted of infrared rays. Joseph von Fraunhofer would later come to discover that by magnifying the spectrum of visible light, gaps in the spectrum would be observed. These Fraunhofer lines would later be determined to be caused by the absorption of light by electrons in moving between atomic orbitals when it passed through atoms, with each atom having a characteristic signature due to the quantum nature of these orbitals. This since has led to the core of astronomical spectroscopy, allowing astronomers to make observations about the composition of stars, planets, and other stellar features through the spectral lines, as well as observing the motion and expansion of the universe, and the existence of dark matter.

Carl Sagan opens the program with a description of the cosmos and the Spaceship of the Imagination. The ship journeys through the universe's hundred billion galaxies, the Local Group, the Andromeda Galaxy, the Milky Way, the Orion Nebula, our Solar System, and finally the planet Earth. Eratosthenes' successful calculation of the circumference of Earth leads to a description of the ancient Library of Alexandria. Finally, the Ages of Science are described, before pulling back to the full span of the Cosmic Calendar.

In May 2009, NASA astronauts embark on a mission to perform maintenance and repairs to the Hubble Space Telescope. As they go about their tasks, danger and beauty are never far away. The nature of space indicates that even the simplest routine can go fatally awry, while amazing photographs taken by the telescope celebrate the wonder of Earth's celestial surroundings.
An IMAX 3D camera chronicled the effort of 7 astronauts aboard the Space Shuttle Atlantis to repair the Hubble Space Telescope.

This episodes the nature of the cosmos on the micro and atomic scales, using the Ship of the Imagination to explore these realms. Tyson describes some of the micro-organism that live within a dew drop, demonstrating parameciums and tardigrades. He proceeds to discuss how plants use photosynthesis via their chloroplasts to convert sunlight into chemical reactions that convert carbon dioxide and water into oxygen and energy-rich sugars. Tyson then discusses the nature of molecules and atoms and how they relate to the evolution of species. He uses the example set forth by Charles Darwin postulating the existence of the long-tongued Morgan's sphinx moth based on the nature of the comet orchid with pollen far within the flower. He further demonstrates that scents from flowers are used to trigger olfactory centers in the brain, stimulating the mind to threats as to aid in the survival of the species. Tyson narrates how Greek philosophers Thales and Democritus postulated that all matter was made up of combinations of atoms in a large number of configurations, and describes how carbon forms the basic building block for life on earth due to its unique chemical nature. Tyson explains on the basic atomic structure of protons, neutrons, and electrons, and the nature of nuclear fusion that occurs in most stars. He then discusses the existence of neutrinos that are created by these nuclear processes in stars, and that detecting such sub-atomic particles which normally pass through matter require subterranean facilities like the Super-Kamiokande that were used to detect neutrinos from the supernova SN 1987A in the Large Magellanic Cloud before light from the explosion were observed due to their ability to pass through matter of the dying sun. Tyson compares how neutrinos were postulated by Wolfgang Pauli to account for the conservation of energy from nuclear reactions in the same manner as Darwin's postulate on the long-tongued moth. Tyson concludes by noting that there are neutrinos from the Big Bang still existing in the universe but due to the nature of light, there is a "wall of infinity" that cannot be observed beyond.

There is one vibratory field that connects all things. It has been called Akasha, Logos, the primordial OM, the music of the spheres, the Higgs field, dark energy, and a thousand other names throughout history. The vibratory field is at the root of all true spiritual experience and scientific investigation". It is the same field of energy that saints, Buddhas, yogis, mystics, priests, shamans and seers, have observed by looking within themselves. Many of history's monumental thinkers, such a Pythagoras, Kepler, Leonardo DaVinci, Tesla, and Einstein, have come to the threshold of this great mystery. It is the common link between all religions, all sciences, and the link between our inner worlds and our outer worlds. Inner Worlds was created by Canadian film maker, musician and meditation teacher Daniel Schmidt. The film could be described as the external reflection of his own adventures in meditation. As Daniel came to meditative insights, he realized that these same insights were discovered over and over in spiritual traditions around the world and that all traditions share a common mystical underpinning. He realized that it is this core experience that connects us not only to the mysterious source of all creation, but to eachother as well.

Ignited by the power of the atom, burning with light, heat and wrath, stars are anything but peaceful. They collide, devour each other, and explode in enormous supernovas--the biggest explosions in the Universe.