Shellstar grew up in a small colony of cats, containing three families hunting and living together. Living at the shores of the sea, she had to learn a lot of things: To withstand the harsh winds for example or to specialize in finding fresh water. The various birds living at the sea weren't easy to catch either. All of these were necessities to survive, but still, she loved her home and doing her part in the colony. 

But what young Shellstar loved the most of all things, were stories. And her parents had a lot to tell. 

There were the vast adventures of her mother, who had lived on a ship in her youth and traveled around the world, before eventually settling down with her father. Truly, This sparked her interest in traveling and exploring new places.

But the stories of her dad fascinated her even more: He told her about her great, great grandfather Greystar, the most famous leader of ShoreClan, who had lived in and protected these lands with the help of his followers. He told her About Greystars adventures: How he had saved the clan from a flood or from aggressive rats, just as Fishnoses own parents had told him before. He wasn't entirely sure though, how ShoreClan vanished, leaving behind only this small group of cats, who slowly forgot about the old traditions - or ceased caring for them.

Shellstar couldn't accept the fact, that these traditions were about to be forgotten and it was then when the idea of founding a new ShoreClan popped up in her head. But her family and the other cats of the colony didn't seem to be that passionate about some old clan their ancestors lived in. They had enough to do to survive. They didn't want to worry about stories. 

The only one who seemed to share her fascination was her adopted brother Salty. As kits, they often pretended to be the great leader Greystar and his best friend Silverpelt, the medicine cat of the clan (Salty insisted on being a medicine cat) and reenacted the stories their father had told them.  
Shellstar probably would have continued to only dream about founding a clan, if it wasn't for the harsh storm, which shook her homeland for several days, destroying the colony's dens and drove away their prey. A lot of cats died - some were caught by the huge waves, with no way to escape, until they eventually drowned. Others just vanished, caught by the strong gusts of wind and were later found dead. Her father and older sister were two of them. 

The cats had to flee to save their lives, scattered in all directions, leaving their home behind. 

It was then when Shellstar decided to go on a journey to find cats who shared her passion for founding a clan. To then, one day, gloriously return to her homelands and follow the path of Greystar and the old ShoreClan.

However, the only cat who was willing to follow her was her brother Salty. The other cats just silently shook their heads, deeming her idea stupid and doomed to fail. Disappointed but not discouraged, they named themselves Shellstar and Saltypelt, after Greystar and Silverpelt, and left their family to start their adventurous quest.