Book #1 in the Save the Multiverse series. Fifteen-year-old genius Eddie Hertz and his twelve-year-old sister Samantha have lost their mother-but they refuse to lose their family. When their homemade multiverse portal finally works, the siblings tumble through time and reality, landing in 1871 Chicago on the terrifying eve of the Great Chicago Fire. There they find their mother transformed into a mysterious prophetess, desperately warning the city of the coming disaster. But something far darker is at work: a deadly "seed of catastrophe" is threatening to unravel history itself. Racing against flames and fate, Eddie and Samantha must destroy the seed, outsmart a sinister steward with deadly plans aboard the RMS Titanic, and master extraordinary new powers-Samantha's glowing skirt of positive energy and Eddie's wildly unpredictable inventions. One misstep could collapse entire timelines, erasing hundreds of lives and destroying their only chance to bring their mother home. Blending heart-pounding adventure, clever inventions, time-crossing mystery, and the unbreakable bond between siblings, When Mom Left the Universe is a thrilling multiverse journey about courage, family, and the power of hope across realities.