*While this miniseries was published a good while after the inception of the series (the kick-off issue of this series being the 39th BPRD stand-alone story), it is a story arc with threads taken from very early in the Mignola-verse, with many of the elements being laid out in the Hellboy: Wake the Devil series. When Hellboy's origin story was set in 1944 at the close of World War II, it left a gap of time which Mignola saw as an opportunity to weave plot threads to strengthen his current plots. This series, B.P.R.D.: 1946 is the first of several 5-issue limited series which deals with this time period. In them, we see the continued adventures of Trevor Bruttenholm and his young charge, the infant Hellboy.
In this arc, we see the first of the new agency, the remnants of the Nazi forces which brought Hellboy to Earth, and the fallout from their failed association with vampire Giurescu, code named Project Vampir Sturm. We also meet the BPRD's sinister Russian equivalent, and its leader, the other-worldly Varvara.
This series was followed by B.P.R.D.: 1947 and B.P.R.D.: 1948. *Source: Warlock