Is this plant dead?

Back from three weeks away, or an inherited plant that looks beyond help.

Tell me whether this plant is dead, salvageable, or simply ugly. Give me the test that settles it: scratch the stem for green, check whether the roots are white and firm or brown and soft.

If it is salvageable, the first three things to do, in order. If it is dead, say so in your first line and tell me what can be propagated from what is left.

The plant and what happened to it:

Diagnosis and rescue. Working out what is wrong with a plant, what is eating it, and whether it is worth saving at all.