Calcium is a vital element for life, which underlies every thought and every movement. Behind the scenes, this invisible signal has shaped the greatest ideas and feats in the history of living things. In illness, its vitality means calcium often participates in disease. Our lab investigates how calcium imbalance contributes to Duchenne muscular dystrophy, a devastating childhood muscle disorder. To observe this silent play, we engineered nematode worms whose muscles produce fluorescent markers in distinct colors, each targeted to a specific compartment of the muscle cell. Blue light marks calcium stored in the sarcoplasmic reticulum at rest. Green records its rush into the sarcoplasm to trigger contraction. Red reveals its capture by mitochondria that must match the energy supply to the force. Using advanced molecular and imaging tools, we can follow this colorful calcium dance in freely moving animals and link its beauty to both health and disease.