When he hatches from his egg, Sepio, a baby Bobtail Squid, is not able to glow. His dark shape is too obvious in the moonlit water and all kinds of predators lurk nearby. Ali, an intrepid Vibrio Fischeri Bacterium, is determined to reach safety too. Can Ali and Sepio help each other? This is a beautifully illustrated storybook about the symbiotic relationship between the Hawaiian Bobtail Squid and the bioluminescent bacteria (Vibrio fischeri) that help it glow in the moonlight. Originally published in 2014, this book has been extensively re-written and revised to delight and captivate primary school-aged readers.