Roots: 1984 (the methodology of the 'Hate Room' recalls daily 'peace' rituals practiced over an image of Big Brother). The Doctor refers to Groundhog Day in episode three and in episode four quotes Edmund Burke ('When bad men combine, the good must associate; else they will fall one by one, an unpitied sacrifice in a contemptible struggle")
Continuity: Ace studied the War Poets in school - particularly Wilfred Owen and Siegfried Sassoon. She tells Hex that she has run into her mother a couple of times [since joining the Doctor], as well as her brother - but regards the Doctor and Hex as her family for now.
Hex recalls his grandmother again (see: Links) says his father never told him about his mother, who he names Sandra Elizabeth Schofield (i.e. Cassie). His one photograph of her is still in his room in Shoreditch where he left it by accident before joining the Doctor and Ace (The Harvest).
The Doctor refers to himself as having "six" senses.
Links: Ghost Light. The Forge reappears in Project Twilight and Project Lazarus (as do Hex's mother and, latterly, the young Hex). One of Ace's professed meetings with her mother may be that of The Curse of Fenric, while she meets her brother in The Rapture. Hex first mentions his father and grandmother bringing him up in Live 34.
Location: Charnage hospital and surrounds (the titular No Man's Land), Northern France, 1917.
The Bottom Line: "A trained soldier without a moral compass is one of the most frightening things of all"