After a charge that Blutch has managed to avoid, which in fact creates a scramble with Chesterfield, the corporal gets apostrobed by a infantryman who is perfectly unknown to him... The latter, Jonas Nutcracker, seems to see in Blutch his own son Barnaby; and for cause, Blutch and Barnaby look like two drops of water! But thanks to a scar on the chest that Blutch does not possess, the old Nutcracker has to go to the obvious... In front of the disarray of the latter, Blutch decides to give him a hand. Barnaby, who was "sounded" during an explosion, is currently in an asylum of soldiers. But Jonas is convinced that by leaving his son from the asylum and reviving a past action that he could easily heal... Blutch, by a skilful stratagem, will help Jonas and Barnaby by replacing him in the asylum... He will only be left to wait a few days and then to escape. A formality for him who is as healthy as he is! A formativeity... Finally, that'sickness for him... It's not enough to disturb his own.