Possible Clues:

• Swiss mountain
• 'The __ Sanction' (1970s thriller)
• Peak in the Bernese Alps
• Swiss peak
• Peak near the Jungfrau
• 'The ___ Sanction' (1970's thriller)
• 'The ___ Sanction' (Eastwood film)
• Trevanian's The ___ Sanction
• Peak in an Eastwood film
• Peak in a Trevanian title