Back on American ground, by way of the Strait

Black Ball Ferry Line runs the MV Coho between Victoria, British Columbia and Port Angeles, Washington: 22.59 nautical miles, roughly 42 kilometres, about ninety minutes across the Strait of Juan de Fuca, into a dock at 101 East Railroad Avenue in downtown Port Angeles. The ship was launched in 1959 and carries up to 1,000 passengers and 110 vehicles. Port Angeles is a U.S. Customs and Border Protection port of entry, so Day 30 starts with a passport in hand and only becomes a walking day once she is through the hall and out on the waterfront.

From there the route turns east along the water on the Olympic Discovery Trail, which runs about four miles of flat, paved shoreline between downtown Port Angeles and the Morse Creek trailhead. Day 30's 4.4 miles are essentially that stretch, walked outbound. It is the gentlest leg in this chapter and the only one that begins on a boat.

The border is the point. Jada Bascom's donor was not in Washington and not in British Columbia. Torsten Huber was on DKMS's register in Germany — one organisation, founded in 1991, that now lists more than 13 million registered donors across seven countries. Registries are national; the search is not. The World Marrow Donor Association's global network lists 44 million stem cell donors and more than 750,000 cord blood units from registries and cord blood banks in more than 57 countries, and its Search & Match Service exists, in its own words, to make cross-border transplants "safer, faster, and more reliable."

So a customs queue is a reasonable thing to walk through on this particular day. Three quarters of patients who need a transplant have no fully matched donor in their own family. For them the answer, if there is one, is a stranger — and the stranger is as likely to live on the other side of an ocean as on the other side of the Strait.