All That Glisters

Once again Alistair Devenish is involved in a cross-Channel chase following the heist of valuable bronzes from a church outside Milan. Sold at auction, these have vanished before the new owner could pick them up. A whisper tells him that they have been taken abroad perhaps via a yacht berthed in Monaco, Alistair picks up the chase. He must interview people in Milan but the chief suspect has vanished. The old Cure at the church is feeble and frail; does he know more than he is letting on?
Alistair's exotic French fiancée, Isabelle, arrives in Monaco for the weekend. Out for a walk in the harbour, she mistakenly goes on board the huge yacht which Al has spoken so much about. The yacht leaves, she panics and hides on board; in the same space, is an Italian secret police man who has stumbled on a few of the bronzes; both their phones die after a few scrambled words; what to do?
Alistair learns in Milan that the old cure, together with a young man, have left for Genoa to rendezvous with the yacht, taking sacks of apparently heavy goods. He races to the Port at Genoa and with the Italian maritime police they pursue the yacht to sea.
Finally, caught out at sea and held to account, the bronzes on board are recovered but are they the bronzes? Not what they seem; one of them leaks a substance; what is it?