Martyn Dipper is a martial arts instructor from Wiltshire who faced a T4 throat cancer diagnosis in late 2021. Told the tumour was too large to operate on, he was offered a place on a cutting-edge clinical trial for Proton therapy at The Christie in Manchester. He completed every session. He rang the bell. In the summer of 2023, he swam the English Channel — one hour at a time. Unmasked is his account of what that journey actually looked like, and the mindset that carried him through it.