The rock, a titan's discarded toy, jutted from the shimmering expanse that was once Atlantis. Perfect weather, she thought, for adventure. Coral castles and kelp forests danced unseen beneath her as she sat perched, tail swaying gently in the currents, a shimmering cascade of emerald and sapphire. This was her waiting rock. Serena was late. Again.

  A sigh, barely audible over the rhythmic pulse of the ocean, escaped her lips. Serena, with her impulsive spirit and reckless curiosity, was always late. Their adventures usually involved something forbidden: a glimpse of the sun-drenched world above, a stolen trinket from a sunken ship, or, on one memorable occasion, a brief tango with a playful dolphin.

  Today, they were set to explore a newly exposed stretch of dry land, a consequence of the shifting tides and a forgotten tremor deep beneath the seabed. The idea alone quickened her pulse. She hoped Serena hadn't gotten sidetracked. The lure of the unknown, the rustle of unseen leaves… it was all too exciting to miss together. She hoped her sister will come soon.