Notice these expressions in the text. Infer their meanings from the context.

Explanation

Keep body and soul together - to manage to keep alive, to survive
hunger gleamed in his eyes - feeling so hungry that the expression shows on one's face
plods along the road - moving along the road slowly but deliberately, to walk with a heavy feet
unwonted joy - unusual pleasure or happiness
impenetrable prison - impassable confinement
nodded a haughty consent - indifferent agreement
eased his way - moved himself slowly and carefully
fallen into a line of thought - agreement of thoughts
things have gone downhill - to decline or grow worse and worse