Formerly rebellious Donna is an independent, single mother who owns a small hotel on an idyllic Greek island. She has raised her spirited daughter, Sophie, alone on the island and has never disclosed the identity of Sophie's father. But now, Donna is about to let go, as Sophie's wedding day rapidly approaches. For Sophie's wedding, Donna has invited her two lifelong best girlfriends--practical and no-nonsense Rosie and wealthy, multi-divorcee Tanya--from her one-time backing band, Donna and the Dynamos. But, Sophie has secretly invited three guests of her own--three men who she believes just may be her father.

This adventure, based on the classic Jules Verne novel "Journey to the Center of the Earth," centers on a science professor Trevor Anderson whose unique hypotheses have put him on the fringe of the academic community. But, during an expedition in Iceland, Trevor and his teenage nephew Sean, accompanied by their beautiful local guide Hannah, make a breakthrough discovery that launches them on a thrilling adventure into the unknown. As their journey takes them deep beneath the earth's surface, they travel through never-before-seen-worlds that bring them face-to-face with surreal and unimaginable creatures stretching the bounds of the visionary scientist's own imagination.