Rune is a character you meet in the Thieves Guild. When you speak to him, he tells you about his past:
As a child, Rune washed up on shore after a shipwreck near Solitude, and was found by a local fisherman. Rune could not recall his past, but the fisherman found a rock with strange writing on it. The fisherman named him Rune.
Rune spends all his money trying to find out about his past. Near where he stands, there's a letter addressed to him:
I looked all over Solitude, but I can't find anything in any of the shipwrecks, and the Internet is turning up a blank. Does this shipwreck actually exist - is there any way we can help Rune?