Possible Clues:

• Compulsion to join in general mass
• Alien contrives to secure a spell in the military
• Ancestor in a live re-enactment of compulsory time in the military
• Conscription could be antisocial? Never
• Flying alien contrives to secure a spell in the army?
• Inaction reveals varied activity abandoned in UK
• Moving on can revitalise conscription
• Post-War activity for youngsters that could take place at St Paul's?
• Compulsory period in the forces
• In a period with the military, trains alone, working on weakness