It won't matter if you didn't catch the first series as each episode features a new case.
The Sun
Each episode features a different set of characters — and ends with the ship hitting the iceberg.
The Sun
The same episode features two midwives who assist at home births.
Times, Sunday Times
Every episode features three self-contained stories of patients which are told from beginning to end.
The Sun
Each episode features a different well-known personality encountering endangered species.
Times, Sunday Times