Kepler-444 is an orange K-type dwarf (about 0.76 solar masses, 5,046 K, 0.75 solar radii), 36.4 light-years from Earth. Kepler-444 is an ancient compact system, about 11 billion years old, with five sub-Earth planets around a star from the Galaxy's youth. The system hosts 5 confirmed planets on orbits ranging from 3.6 days to 9.7 days. With 5 confirmed worlds, Kepler-444 is a densely packed system whose resonances, spacing, and formation history are active research topics. Mutual gravitational tugs between the planets can slowly reshape their orbits, preserving clues to the system's assembly. Kepler-444 b skims its star closer than Mercury orbits the Sun. At 0.4 Earth radii, Kepler-444 b is a compact world comparable in size to rocky planets in our Solar System.