Naughtinesses cryptically resulting in plea for help (3)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

We need to split the first word into NAUGHT IN ESSES: it’s O (zero = naught) in SS (two letter S = esses). International distress signal, dot-dot-dot dash-dash-dash dot-dot-dot. Originally defined just as a sequence of dots and dashes, but it corresponds to the letters SOS in Morse code so it’s acquired that name.