Below is an instruction that describes a task. Write a response that appropriately completes the request.

### Instruction:
Who wrote the episode called "mercury falling"?

### Inputs:
table_name: table, columns: ['Ep. No.', 'Title', 'Director', 'Written by', 'Original Air Date', 'Production No.']

### Response:
SELECT Written by FROM table WHERE Title = "Mercury Falling"