Tilly and Milly are a pair of seven-year-old identical brown-haired superhero twins. Despite them being identical, they have completely different personalities and superpowers. Tilly's superhero name is 'Sparkle Fairy', and she always wears a pink long-sleeved full-body jumpsuit covered in sparkles, a pair of pink sparkly swimming goggles, a pair of pink sparkly rubber gloves, a pair of pink sparkly rubber boots and a pair of pink sparkly fairy wings. She has the power to fly and shoot sparkles from her hands. Milly, on the other hand, is known as 'Super Swimmer', and she always wears a blue long-sleeved full-body rubber wetsuit, a pair of dark blue swimming goggles, a pair of black rubber gloves, a pair of light blue flippers, an ocean blue swimming cap with bubbles all over it, a blue superhero cape, a pair of blue nose-clips and a purple snorkel. She has the power to hold her breath underwater for a really long time and swim very fast. Tilly is very bubbly, friendly and joyful, while Milly is very shy, anxious and timid.