The last man on Earth has company

He has been alone since she died. Since they all died. He wants to believe that there are other people out there, but the evidence suggests that isn't the case. He comes to accept that he is the only one left, until the morning when he wakes up to find that it has snowed and there are footprints outside his window. He follows them in the hope of finally finding other people like him, but the longer the chase goes on, the more he questions what he is seeing and his own sanity.