Thunder, rain and emptiness

Hikaru leaves forgetting to do the one thing he does every day then a thunder storm comes along. Now Kaoru is scared and alone. What happens when he isn't there when Hikaru returns? A run away? A kidnapping? Is Kaoru ok and where is he? The truth could shatter one of their worlds forever. Warnings: at least mention of rape, death, depression and at least some yaoi. M for safety.