 Today the Little Einsteins are playing on the beach along with two best friend little hermit crabs. The crabs have a special friendship song they love to sing together, a song so beautiful it makes everyone feel friendly. But just then a big wave washes one of the crabs far out to sea, separating the two best friends. The Little Einsteins go on a daring undersea mission to bring the crabs back together, traveling through the Gulf Stream, past coral reefs and an undersea tunnel maze. Most treacherous of all - they have to watch out for a very unfriendly-seeming shark! With the power of the friendship song, the Little Einsteins manage to reunite the hermit crabs and they even make one last unexpected friend.