Shetland BBC1, 9pm
New series. On board the Aberdeen to Shetland ferry, a woman witnesses an altercation between two men - one of whom subsequently goes missing. Later, a young boy is admitted to intensive care after consuming pills he mistook for sweets found on the beach. DI Jimmy Perez searches the shoreline and recovers a rucksack containing more pills and a ferry ticket - which a hooded figure tries to snatch from him. Now a connected missing persons and drugs case, matters gather pace after a body is found in grisly circumstances. Mystery drama, starring Douglas Henshall.