A to Z Challenge - X is for X marks the spot

The A to Z challenge is to write a daily blog post centred around a different letter of the alphabet each day. I will attempt to write a complete story which will continue each day and hopefully draw to a conclusion when we get to Z.
For previous posts click a letter - A , B , C , D, E , F , G, H, I,  J, K, L, M, N, O, P, Q, R, S, T, U,V , W

Paul held his breath, trying not to move or make a sound as he stared into the Doberman’s eyes. The dog stood completely still, panting hard. It looked...