This is the tragic moment a firefighter desperately tries — but fails — to get inside a burning Harlem apartment in time to save those inside early Wednesday.

Video captured by neighbor Angel Cardenas shows the solitary smoke eater standing on a fire escape, using a special hook in repeated attempts to break his way inside — as flames shot out of the apartment in front of him.

A 45-year-old mom, her 11-, 8- and 6-year-old daughters and 3-year-old son were killed in the blaze at the Samuels Houses on Seventh Avenue near 142nd Street in Harlem that broke out around 1:40 am.

A 33-year-old man, who authorities believe was either the woman’s stepbrother or stepson, was also killed.

None of the victims were immediately identified, pending family notification.