One Piece, Vol. 15, Paperback/Eiichiro Oda

Nami's sickNow the Merry Go is without her navigatorLuffy and crew have but one choice--find land and hopefully a doctor. They miraculously stumble upon Drum Island where it is eternally winter, but upon arriving they find out the island has only one doctor--and she's a witchWith Nami's life on the line, Luffy sets out through the snow-laden fields to find this doctor, witch or not