CHAPTER ONE<br >ONLY ONE NEWSPAPER CARRIED THE STORY IN DETAIL， UNDER THE<br >headline: TREASURES STOLEN FROM MUSEUM.<br > Several Celtic works of art were stolen from the British<br >Museum yesterday， one of them worth more than ~50，000.<br >Police say that the theft appears to be the result of an<br >intricate and so far baffling plan. No burglar alarms were<br >set off， the showcases involved were undamaged， and no<br >signs have been found of breaking-in.<br > The missing objects include a gold chalice， three jewelled<br >brooches and a bronze buckle. The chalice， known as the<br >Trewissick Grail， had been acquired by the Museum only<br >last summer， after its dramatic discovery in a Cornish cave<br >by three children. It had been valued at ~5o，ooo， but a<br >Museum spokesman said last night that its true value was<br >"incalculable，" due to the unique inscriptions on its sides<br >which scholars have so far been unable to decipher.<br > The spokesman added that the Museum appealed to the<br >thieves not to damage the chalice in any way， and would<br >be offering a substantial reward for its return. "The grail<br >